Open Migrator/LM for UNIX and Linux CLI · EMC Corporation Corporate Headquarters: Hopkinton, MA 01748-9103 1-508-435-1000 EMC Open Migrator/LM for UNIX and Linux CLI Version 3.10

EMC Open Migrator/LMfor UNIX and Linux CLI

Version 3.10

PRODUCT GUIDEP/N 300-002-732

REV A04

®

EMC CorporationCorporate Headquarters:

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Copyright © 2005 - 2007 EMC Corporation. All rights reserved.

Published July, 2007

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EMC Open Migrator/LM for UNIX and Linux Version 3.10 CLI Product Guide

Contents

Contents ................................................................................................... 3

Figures....................................................................................................... 7

Preface ..................................................................................................... 9

Chapter 1 Product OverviewOverview............................................................................................ 14Requirements and considerations .................................................. 17

Requirements ..............................................................................17Considerations ............................................................................17

Open Migrator/LM functions......................................................... 20Concurrent migrations...............................................................20Data migration to a different volume type .............................20Data migration to a different volume size ..............................20Data synchronization .................................................................20Migration persistence and mirror synchronization...............21Log files ........................................................................................21

Migration planning........................................................................... 23I/O stack layers...........................................................................23Disk space considerations .........................................................24Migration with a volume manager ..........................................24Provisioning target volumes .....................................................24Migration with a file system .....................................................25Application performance considerations................................25

Open Migrator/LM command summary ..................................... 27

EMC Open Migrator/LM for UNIX and Linux Version 3.10 CLI Product Guide 3

Contents

Chapter 2 InstallationPreinstallation tasks.......................................................................... 30Installing Open Migrator/LM on HP-UX..................................... 31

Disk space considerations ......................................................... 31Files added during install.......................................................... 32Session activation ....................................................................... 33Removing the software from HP-UX ...................................... 34

Installing Open Migrator/LM on IBM AIX.................................. 36Disk space considerations ......................................................... 37Files added during install.......................................................... 37ODM modifications................................................................... 38Removing the software from IBM AIX ................................... 38

Installing Open Migrator/LM on Sun Solaris .............................. 41Disk space considerations ......................................................... 41Files added during install.......................................................... 42Removing the software from Sun Solaris ............................... 43

Installing Open Migrator/LM on Linux ....................................... 46Disk space considerations ......................................................... 47Files added during install.......................................................... 47Removing the software from Linux......................................... 48

Chapter 3 Open Migrator/LM Control OperationsSession overview .............................................................................. 52

Migrating data between storage arrays................................... 52Control operations............................................................................ 54

Creating a device file.................................................................. 54Creating a session....................................................................... 57Adding devices to a session...................................................... 60Listing sessions .......................................................................... 61Showing session data................................................................. 61Activating a session.................................................................... 62Start device copying................................................................... 63Pausing the session .................................................................... 63Deleting a session ....................................................................... 65Restarting a failed session ......................................................... 65Tuning session performance..................................................... 66Verifying session states.............................................................. 72Querying session status............................................................. 73Comparing session data ............................................................ 75Setting environmental variables............................................... 75Display session properties ........................................................ 76

EMC Open Migrator/LM for UNIX and Linux Version 3.10 CLI Product Guide4

Contents

Clean up old session data ..........................................................76Postmigration procedures .........................................................77

Appendix A Command ReferenceConventions ....................................................................................... 80stormigrate ......................................................................................... 81

Appendix B ExamplesMigrating Oracle databases ............................................................. 92

Identifying devices to migrate ................................................. 92Creating volume groups and logical volumes on target devices ..........................................................................................98Setting up EMC Open Migrator/LM.....................................101Creating the Session .................................................................103Activating the session...............................................................104Managing the session ...............................................................105Completing the migration .......................................................108Conclusion .................................................................................112

Index ..................................................................................................... 113

5EMC Open Migrator/LM for UNIX and Linux Version 3.10 CLI Product Guide

Contents

EMC Open Migrator/LM for UNIX and Linux Version 3.10 CLI Product Guide6

Title Page

Figures

1 Open Migrator/LM copy session ................................................................ 162 I/O stack layers .............................................................................................. 233 Data migration using the stormigrate command ...................................... 534 Using Solutions Enabler to determine the schema of Oracle database .. 935 Determining database files to be migrated ................................................. 946 Detail showing the location of database file ............................................... 957 Determining disk groups associated with Oracle database ..................... 968 Identify logical volumes and file system with schema SYS ..................... 979 Identify logical volumes and file system with schema TPCB .................. 9710 Configuration details of logical volume tpcb01 in schema TPCB ........... 9811 Creating target volume groups using EMC CLARiiON devices ............ 9912 Comparing source and target logical volume pairs ................................ 10013 Device file listing the source and target logical volumes ....................... 10114 Setting environmental variables ................................................................ 10215 Creating the Open Migrator/LM session ................................................. 10316 I/O activity on source logical volumes ..................................................... 10417 Activating and starting the copy process for the session ....................... 10518 Increased IO activity due to copy in process ........................................... 10619 Tuning IO size for the session .................................................................... 10720 Pausing and resuming the session ............................................................. 10821 Verify and stop Oracle database before completing the migration ...... 10922 Unmount source devices and deactivate the session .............................. 11023 Starting Oracle on target devices ............................................................... 11124 Testing the integrity of the Oracle database on target devices .............. 112


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Figures


Preface

As part of its effort to continuously improve and enhance the performance and capabilities of the EMC product line, EMC periodically releases revisions of its hardware and software. Therefore, some functions described in this document may not be supported by all versions of the software and hardware currently in use. For the most up-to-date information on product features, refer to your product release notes.

If an Open Migrator/LM for UNIX and Linux feature does not function properly or does not function as described in this guide, please contact the EMC Customer Support Center for assistance.

Audience This document describes the functionality and use of the Open Migrator/LM for UNIX and Linux software, version 3.10, and provides both guide and reference information for command line users and script programmers.

This document is intended for system administrators who are tasked with a large data migration effort where system availability and data integrity is critical. Prerequisite knowledge includes familiarity with the following topics:

◆ Data volume migration

◆ UNIX and your specific operating system environment

◆ Linux and your specific operating system environment


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Preface

Organization Here is an overview of where information is located in this guide:

Chapter 1, ”Product Overview,” provides a functional overview of Open Migrator/LM, describes the data migration process, and introduces the stormigrate command line interface.

Chapter 2, ”Installation,” describes how to install Open Migrator/LM for UNIX and Linux on the various supported host platforms.

Chapter 3, ”Open Migrator/LM Control Operations,” explains how to use the stormigrate command line interface.

Appendix A, “Command Reference,” describes the stormigrate command arguments and available options.

Appendix B, “Examples,” presents examples that use the stormigrate command for data migration operations.

Relateddocumentation

Related documents include:

◆ EMC Open Migrator/LM for UNIX Version 3.10 Release Notes.

◆ EMC Open Migrator/LM for Linux Version 3.10 Release Notes.

Conventions used inthis document

EMC uses the following conventions for special notices.

Note: A note presents information that is important, but not hazard-related.

CAUTION!A caution contains information essential to avoid data loss or damage to the system or equipment. The caution may apply to hardware or software.

IMPORTANT!An important notice contains information essential to operation of the software. The important notice applies only to software.


Preface

Typographical conventionsEMC uses the following type style conventions in this document:

Normal Used in running (nonprocedural) text for:• Names of interface elements (such as names of windows,

dialog boxes, buttons, fields, and menus)• Names of resources, attributes, pools, Boolean expressions,

buttons, DQL statements, keywords, clauses, environment variables, filenames, functions, utilities

• URLs, pathnames, filenames, directory names, computer names, links, groups, service keys, file systems, notifications

Bold: Used in running (nonprocedural) text for:• Names of commands, daemons, options, programs,

processes, services, applications, utilities, kernels, notifications, system call, man pages

Used in procedures for:• Names of interface elements (such as names of windows,

dialog boxes, buttons, fields, and menus)• What user specifically selects, clicks, presses, or types

Italic: Used in all text (including procedures) for:• Full titles of publications referenced in text• Emphasis (for example a new term)• Variables

Courier: Used for:• System output, such as an error message or script • URLs, complete paths, filenames, prompts, and syntax when

shown outside of running text.

Courier bold: Used for:• Specific user input (such as commands)

Courier italic: Used in procedures for:• Variables on command line• User input variables

< > Angle brackets enclose parameter or variable values supplied by the user

[ ] Square brackets enclose optional values

| Vertical bar indicates alternate selections - the bar means “or”

{ } Braces indicate content that you must specify (that is, x or y or z)

... Ellipses indicate nonessential information omitted from the example


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Preface

Where to get help EMC support, product, and licensing information can be obtained as follows.

Product information — For documentation, release notes, software updates, or for information about EMC products, licensing, and service, go to the EMC Powerlink website (registration required) at:

http://Powerlink.EMC.com

Technical support — For technical support, go to EMC Customer Service on Powerlink. To open a service request through Powerlink, you must have a valid support agreement. Please contact your EMC sales representative for details about obtaining a valid support agreement or to answer any questions about your account.

Your commentsYour suggestions will help us continue to improve the accuracy, organization, and overall quality of the user publications. Please send your opinion of this document to:

[email protected]


http://powerlink.emc.com

1Invisible Body Tag

This chapter provides a functional overview of the EMC® Open Migrator/LM for UNIX and Linux, describes the data migration process, and introduces the stormigrate command line interface.

◆ Overview............................................................................................. 14◆ Requirements and considerations ................................................... 17◆ Open Migrator/LM functions.......................................................... 20◆ Migration planning............................................................................ 23◆ Open Migrator/LM command summary ...................................... 27

Product Overview

Product Overview 13

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Product Overview

OverviewEMC Open Migrator/LM (Live Migration) for UNIX and Linux provides an online data migration and comparison tool for high availability data centers, where data copying between storage arrays is performed from the production host. Open Migrator/LM is implemented as a host-based kernel driver and command line interface (CLI), and is used to migrate data from source to target volumes with only a single disruption to the server or applications. Because the Open Migrator/LM device driver is dynamically loaded and unloaded, there is no required system reboot.

Note: The name Open Migrator/LM as used throughout this guide refers only to the UNIX and Linux operating system version of this software product. For information on Open Migrator/LM for a Microsoft Windows operating environment, refer to the EMC Open Migrator/LM for Windows Product Guide.

Open Migrator/LM provides mirroring and background copy functions between storage arrays to synchronize data images on one or more source and target volumes, LUNs, or LUN partitions. Data can be migrated between source and target volumes of any block device type. During migration the source volume can remain available for input/output (I/O) to production host applications. The target volume is set to read/write disabled. The target volume should also be set as not ready to any additional hosts having access to the volume to guarantee that the volume cannot change while copying is in progress. Open Migrator/LM operates in sessions to manage multiple volume pairs uniformly as a group. Control operations are performed by using the stormigrate CLI command. Source and target pairs can be added to a created session or a device file option (-file) can be used to define device pairs. Refer to Table 1 on page 27 for a list of the command line arguments and actions.

Data can also be compared between source and target volumes in an activated session. When comparing, Open Migrator/LM checks if the source and target volumes are identical. Once the data has been migrated, mirroring continues to keep the source and target volumes synchronized, until the session is deactivated.


Product Overview

When volumes have been successfully migrated and the session has been deactivated, Open Migrator/LM can be uninstalled from the kernel I/O subsystem and the production host. Open Migrator/LM allows for multiple concurrent migrations, while allowing full read and write access to the source volumes. Data synchronization is maintained by capturing and mirroring all I/O to the source volumes in coordination with background copy process I/O.

Due to the complexity of a data storage environment, which may include various applications for file systems, volume managers and multipath capability, it is necessary to understand the I/O subsystem (I/O stack layers) within the operating system (OS) kernel. For best results, source volumes for data migration should always be accessed at the level in the I/O stack that is closest to the application. This avoids certain common problems experienced with LUN level migration underneath logical volumes. For an explanation of the I/O stack layers within a UNIX/Linux OS kernel, refer to “Migration planning” on page 23.

Open Migrator/LM is installed on the production host and is designed to operate as a stand-alone product. Any volumes visible to the production host can be compared and migrated. The source and target volumes can be on the same array or separate arrays. Refer to Figure 1 on page 16.

Overview 15

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Product Overview

Figure 1 Open Migrator/LM copy session

Volumec2t0d55s2

Volumec2t0d56s3

StorageArray 4

Volumeora1_src_vg/rvol2



Data Migration

Copy Session

Note: Data migration is performed through the Production Host, which is running EMC Open Migrator/LM for UNIX and Linux. The host must be able to see all devices in the session.

StorageArray 2

Volumeora1_tgt_vg/rvol1



StorageArray 1

Volumec1t6d0s2

Volumec1t1d3s2

Volumec1t4d2s2

StorageArray 3

Application

EMC Open Migrator/LM

Device Control

SourceDevices

TargetDevices

Data Migration

Data Migration Data Migration Source

Devices

TargetDevices

Volumec2t0d55s4

# A device file contains a list of the copy session volume pairs# The source volume is listed in the first column, target volume is in second column/dev/rdsk/c1t1d3s2 /dev/rdsk/c2t0d55s2/dev/rdsk/c1t6d0s2 /dev/rdsk/c2t0d55s4/dev/rdsk/c1t4d2s2 /dev/rdsk/c2t0d56s3/dev/ora1_src_vg/rvol1 /dev/ora1_tgt_vg/rvol1/dev/ora1_src_vg/rvol2 /dev/ora1_tgt_vg/rvol2/dev/ora1_src_vg/rvol3 /dev/ora1_tgt_vg/rvol3# End file

ProductionHost

{{

{{


Product Overview

Requirements and considerationsOpen Migrator/LM software is based on the functionality and features of associated hardware and software in an EMC Enterprise Storage environment.

RequirementsYou must have one of the following supported operating environments:

◆ HP-UX

◆ IBM AIX

◆ Sun Solaris

◆ Red Hat Enterprise Linux AS

Note: For detailed information on supported UNIX and Linux operating systems and kernel versions, refer to EMC Open Migrator/LM in the E-Lab™ Navigator at http://Powerlink.EMC.com.

Accessed from the Powerlink home page, move the cursor over the Support > Interoperability/Compatibility/Configuration > E-Lab Interoperability Navigator, and click Launch E-Lab Interoperability Navigator.

Note: For information on supported file systems, volume managers and multipath I/O managers, refer to your EMC Open Migrator/LM for UNIX version 3.10 Release Notes or EMC Open Migrator/LM for Linux version 3.10 Release Notes as applicable.

ConsiderationsNote the following considerations for Open Migrator/LM:

◆ Open Migrator/LM has no dependencies on the versions of the EMC Enginuity™ operating environment, EMC Solutions Enabler software, or EMC CLARiiON® Navisphere® software.

◆ Both the source and target volumes remain synchronized until the session has been deactivated.

◆ Open Migrator/LM cannot be used with EMC Celerra® systems.

Requirements and considerations 17

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Product Overview

◆ Open Migrator/LM does not support the following:

• Boot disk or system volume (root file system devices) migration

• Automatic volume expansion

• Migrations for cluster host environments are currently not supported.

◆ With the exception of character devices of the raw(8) driver, Open Migrator/LM for Linux does not support character devices. The software checks that character devices named in add and create commands are raw(8) driver character device special file nodes.

◆ EMC strongly recommends that you do not migrate jfs/jfs2 log volumes on IBM AIX hosts. The log data is only used for recovery and is not needed to mount the target volume cleanly when the copy/compare session has completed.

Open Migrator checks the LV State of all target (native) logical volumes at the time of session activation. If the LV State is open (in use) for shared volumes that are mounted, then session activation is blocked.

CAUTION!Note that if the target loglv is closed (not in use) but volumes sharing the target loglv are either not mounted or not part of the migration, data loss could occur when the source loglv volume is migrated to the target loglv. The file system log for volumes not being migrated could be overwritten.

As a result, file systems that share the target jfs/jfs2 log volume could become inaccessible.

Furthermore, data loss could occur if a target loglv is included in the session, and volumes that are not part of the migration share the target loglv are mounted after the migration starts. Open Migrator exclusively locks the volume when the session begins.

For these reasons, do not include the loglv volumes as part of an OM migration.


Product Overview

◆ Data corruption to volumes may be possible during a copy operation if another host (other than the Open Migrator/LM production host) has write access to the target volume. If this is a concern, it is recommended that the target volume be unmounted or marked as not ready to any other hosts to guarantee that the volume cannot change while the copying is in process.

◆ During peak application I/O load times, user applications may experience a decrease in the response time. Refer to the section titled “Application performance considerations” on page 25 for recommendations on how to improve migration performance.

Requirements and considerations 19

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Product Overview

Open Migrator/LM functionsOpen Migrator/LM allows you to perform various types of data migration operations between storage arrays.

Concurrent migrationsOpen Migrator/LM migrates source and target volume pairs concurrently. Multiple migrations of volume pairs may be executed at one time. The actual number of sessions that can be operated is limited by the availability of your operating system resources at the time of migration.

Data migration to a different volume typeOpen Migrator/LM supports data migration from any type of source block devices to any type of target block devices. In other words, the software allows data migration at the block I/O level between all types of volumes, LUNs, LUN partitions, and devices.

Data migration to a different volume sizeOpen Migrator/LM can migrate data between source and target volumes or meta volumes of different sizes. The target volume must be of equal or larger size than the source volume.

Data synchronizationOpen Migrator/LM provides high availability data synchronization during your data migration operations. While a migration is in progress, the source volume remains fully available for both reads and writes. Open Migrator/LM captures all writes to the source and copies them to the target during the migration process. The target volume is set as read/write disabled to the production host and should be unmounted or set as not ready to any additional hosts having access to the volume to guarantee the volume cannot change during the migration session. Data corruption may be possible during a copy operation if another host has write access to the target volume.


Product Overview

Migration persistence and mirror synchronizationBecause the source volume remains available for I/O to production host applications during a migration, the mirror write consistency of volumes in active sessions cannot be guaranteed across an unplanned reboot or system crash. Open Migrator/LM depends on the orderly shutdown of applications to guarantee mirror synchronization and relies on the execution of an init(8) rc command script at certain run levels to indicate an orderly shutdown.

At system boot time, if an orderly shutdown is not indicated, Open Migrator/LM assumes that pending mirrored writes may have existed at the time of the outage, and that mirror synchronization may have been lost. If mirror synchronization cannot be guaranteed at boot time, Open Migrator/LM will abort the recovery of sessions that were active at the time of the outage.

Active sessions will only be resumed and mirror synchronization guaranteed if the system has been explicitly shut down by using the appropriate system shutdown command (shutdown(8)). The shutdown(8) command is the only reboot or power off method that invokes the init(8) rc command script. Using other methods may cause Open Migrator/LM to abort the recovery of sessions active at the time of the outage.

If the system experiences an unplanned outage or system crash during a data migration, those affected sessions must be activated again and device copying must be started over.

Note: Additionally, when resuming a session, if a session contains tasks with source devices that have VFS mounted filesystems, the recovery will abort because mirror synchronization cannot be guaranteed at boot time.

Log filesOpen Migrator/LM is supported by a log file, which can be used to examine and troubleshoot data migration activities.

A separate log file is created on the system where the Open Migrator/LM service is installed. The log file records all the volume properties. The file is located in the following directory path: /var/EMCom/log.

Open Migrator/LM functions 21

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Product Overview

The /var/EMCom/log file can be viewed by using the standard UNIX display commands for concatenate (cat) and more. The /var/EMCom/log file contains a record of all the command line log messages. The following is an example excerpt from a log file.

2007-06-20 10:10:08.275 15750 CLI command stormigrate create -se cpysess1 was submitted2007-06-20 10:10:08.277 15750 Starting a EMCOM Session Create on cpysess1.2007-06-20 10:10:08.291 15750 The EMCOM session cpysess1 was created successfully.2007-06-20 10:10:25.794 15763 CLI command stormigrate add -se cpysess1 /dev/rdsk/c2t2d100s2 /dev/rdsk/c2t2d102s2 -skip was submitted2007-06-20 10:10:25.810 15763 Starting a EMCOM Session Add on cpysess1.2007-06-20 10:10:25.838 15763 /dev/rdsk/c2t2d100s2 and /dev/rdsk/c2t2d102s2 were successfully added to session cpysess1.2007-06-20 10:10:33.529 15766 CLI command stormigrate act -se cpysess1 was submitted2007-06-20 10:10:33.535 15766 Starting a EMCOM 'Activate' operation on session cpysess1.2007-06-20 10:10:33.569 15766 The EMCOM 'Activate' operation on session cpysess1 was started successfully.2007-06-20 10:10:43.126 15769 CLI command stormigrate copy -se cpysess1 was submitted2007-06-20 10:10:43.135 15769 Starting a EMCOM 'Copy' operation on session cpysess1.2007-06-20 10:10:43.153 15769 The EMCOM 'Copy' operation on session cpysess1 was started successfully.2007-06-20 10:11:22.091 15791 CLI command stormigrate query -se cpysess1 -k -v -i 30 was submitted2007-06-20 10:11:24.201 15800 CLI command stormigrate tune -nt 64 was submitted2007-06-20 10:11:25.449 15800 Starting a EMCOM tune operation.2007-06-20 10:11:25.476 15800 Iosize set to 655362007-06-20 10:11:25.476 15800 Throttle set to 1002007-06-20 10:11:25.476 15800 Nthreads set to 642007-06-20 10:11:25.476 15800 CheckPointSize set to 2562007-06-20 10:11:25.477 15800 Mirror I/O Throttle Performance Ratio set to 2002007-06-20 10:11:25.477 15800 Mirror I/O Throttle Recovery Action set to Terminate2007-06-20 10:11:25.477 15800 The EMCOM tune operation was successful.2007-06-20 10:11:42.476 15801 CLI command stormigrate tune -nt 64 was submitted2007-06-20 10:13:14.662 15840 CLI command stormigrate pause -se cpysess1 was submitted2007-06-20 10:13:14.666 15840 Starting a EMCOM 'Pause' operation on session cpysess1.2007-06-20 10:13:14.686 15840 The EMCOM 'Pause' operation on session cpysess1 was started successfully.


Product Overview

Migration planningThis section provides some basic guidelines for data migration planning with Open Migrator/LM.

I/O stack layersWhen planning a data migration project that uses Open Migrator/LM software for UNIX or Linux, it is important to understand the architecture of your I/O subsystem (or I/O stack) within the server operating system (OS) kernel. This architecture defines the mapping of application data volumes onto physical media. Because data is copied from a source volume I/O stack to a target volume I/O stack, data can be copied at a number of possible levels. Best practice dictates that the user copy data from the source volume I/O stack level that is closest to the application layer. Refer to Figure 2 for a depiction of the various I/O stack levels at which data can be copied.

Figure 2 I/O stack layers

Physical Layer LUN and PartitionSlices

Multi Path I/O Layer

Operating SystemDrivers

Logical VolumeManager Layer Logical Volumes

Mount Points

Application Data

File System Layer

Application Layer

Migration planning 23

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Product Overview

Open Migrator/LM directs RAID1 and copy I/O requests to the source and target volumes by inserting data into the applicable underlying drivers in the volume manager, multipath I/O, and LUN driver layers. The I/O stack level chosen for data migration depends on whether your application’s data volumes are logical volumes or LUNS. Data should always be copied at the highest possible layer in the I/O stack nearest to the application.

Disk space considerationsIn addition to the free disk space required for the installation of Open Migrator/LM on your host system, there should be sufficient space reserved in the /etc file system to store properties files created by the stormigrate utility at run-time. Additional recommended free disk space should be equivalent to 10 KB per device pair in each defined session.

Note: Refer to Chapter 2, ”Installation,” for the amount of free disk space recommended for installation on your specific operating system.

Migration with a volume managerWhen a volume manager is present in the I/O stack, migration should take place at the logical volume level and not at the underlying LUN level. This practice avoids complications that occur with logical volume managers and duplicate disk signatures. Even though, Open Migrator/LM can be used to copy logical volume data at the LUN volume level, this practice is discouraged.

Provisioning target volumesTarget volumes must be provisioned at the level in the I/O stack where the data will be accessed by the application after the migration has completed. If target volumes are logical volumes, the target volumes must be created and made ready for data access by Open Migrator/LM prior to creating the session. This is accomplished by using the volume manager’s administrative tools.


Product Overview

Migration with a file systemIf a file system is part of the I/O stack, the resulting target file system must be the same type as the source. You cannot alter the file system type since migration takes place under the file system in the I/O stack.

Application performance considerationsOpen migrator/LM may have the following affects in your environment:

◆ Increased read I/O load on the source volume/array

◆ Increased write I/O load on the target volume/array

◆ Increased overall I/O load on the Storage Area Network (SAN)

◆ Decreased response time of user applications

The level to which the above affects occur can generally be controlled by setting the tuning I/O ceiling parameter (-ceiling megabytes per second). By default, this value is preset to a conservative 1 Mb/s, which causes no noticeable affect in the performance of most configurations. Extreme care should be used when adjusting this value. When performing online migrations of critical applications, performance of those applications should be monitored closely when increasing the I/O ceiling value.

You must be aware of and take into account your peak application I/O load times when adjusting this value. The I/O ceiling parameter only controls I/O load during the actual copy and compare operations and has no affect on volumes in the mirroring or paused state. When migrating volumes from a faster array to a slower array, write performance on the host will be limited to that of the slower array as long as the session is active in either the copy/compare or mirroring/paused states.

When performing migrations on multiple hosts within a SAN environment, you should monitor for any potential I/O bottlenecks (for example, Inter-switch links (ISLs) and remote storage connections). Exceeding the bandwidth on these links could have a detrimental affect on the performance of your applications that could result in application outages.

Migration planning 25

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Product Overview

Prior to performing online migrations, EMC recommends the following guidelines to help avoid I/O load issues and decreased application response times:

◆ Review the system and hardware logs to identify any potential hardware issues

◆ Verify any storage vendor specified I/O time-out settings for both your source and target device

◆ Avoid migrating temporary data files such as page/swap or database redo logs, as these will add unnecessary I/O load to the system. Generally, files of these types will not be needed once a clean transition is made to the migrated volumes.

Note: Refer to “Tuning session performance” on page 66 for information on the available stormigrate tuning parameters.


Product Overview

Open Migrator/LM command summaryThe Open Migrator/LM command (stormigrate) allows you to perform copy, control and comparison operations between volumes that are accessible to the production host within a session.

Table 1 summarizes the stormigrate commands that you can use to manage an Open Migrator/LM session.

Note: For a more comprehensive description of the stormigrate command and its functionality, refer to Appendix A, “Command Reference.”

Table 1 Open Migrator/LM stormigrate command summary

Command Argument Action

stormigrate activate Activates the session.

add Associates source and target volumes with a created session.

cleanup Cleans up old session data to restore system to a clean state.

compare Compares source and target volume data in an activated session.

copy Begins the copying process for volume pairs in an activated session.

create Defines a new session and assigns a session name.

deactivate Deactivates an activated session.

delete Deletes the session.

list Lists all currently defined sessions.

pause Pauses a session and temporarily stops the operation.

props Displays properties for defined sessions.

query Queries for the status of a given session.

restart Restarts a failed session.

resume Resumes a paused session and begins the operation from where it was paused.

show Displays current configuration data for a given session.

tune Tunes session performance at the kernel level.

verify Verifies the existing state of a given session.

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Product Overview


2Invisible Body Tag

This chapter describes how to install and remove Open Migrator/LM for UNIX and Linux on the various supported platforms.

◆ Preinstallation tasks........................................................................... 30◆ Installing Open Migrator/LM on HP-UX ...................................... 31◆ Installing Open Migrator/LM on IBM AIX ................................... 36◆ Installing Open Migrator/LM on Sun Solaris ............................... 41◆ Installing Open Migrator/LM on Linux......................................... 46

Installation

Installation 29

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Preinstallation tasksBefore you run the installation program, be sure to do the following:

❑ Review the requirements listed in Chapter 1, ”Product Overview” and in the EMC Open Migrator/LM for UNIX and Linux Release Notes.

❑ Check the operational platform support for your system.

Note: For detailed information on supported UNIX and Linux operating systems and kernel versions, refer to EMC Open Migrator/LM in the E-Lab Navigator at http://Powerlink.EMC.com. Accessed from the Powerlink home page, move the cursor over the Support > Interoperability/Compatibility/Configuration > E-Lab Interoperability Navigator, and click Launch E-Lab Interoperability Navigator.

❑ Verify that you have administrative privileges, as they are required to install and run Open Migrator/LM in the kernel.

❑ Install the software according to the instructions provided for your specific operating system (HP-UX, IBM AIX, Sun Solaris, or Red Hat Enterprise Linux AS).

❑ If a previous version of Open Migrator/LM for UNIX/Linux software is currently installed, you must first remove it before installing the new version. Refer to the software removal instructions for your specific operating system located in this chapter.


Installation

Installing Open Migrator/LM on HP-UXThis section describes how to install Open Migrator/LM for UNIX software on a HP-UX host.

Note: If an existing version of Open Migrator/LM for UNIX software is currently installed, it must first be removed before installing another version. Refer to “Removing the software from HP-UX” on page 34.

Note: EMC recommends that the HP-UX kernel tunable parameter for nflocks be set to 1024 before installation.

Perform the following steps to install Open Migrator/LM software on a HP-UX host:

1. Log in to the host system as root.

2. Copy the installation image .tar file to the /tmp directory. For example, type the following command:

cp EMComlm.HPUX.tar /tmp

3. To install the software, type:

swinstall -s /tmp/EMComlm.HPUX.tar EMCom

Note: If this is a reinstall, note that all of the previously set tuning option parameters (-ceiling, -iosize, -checkpointsize, -nthreads, -mio_perf_ratio, and -mio_recover_action) must be manually reset. Refer to “Tuning session performance” on page 66.

Disk space considerationsRecommended free disk space for installation on a HP-UX host is 14 MB. In addition to the install footprint outlined in “Files added during install” on page 32, there should be sufficient space reserved in the /etc file system to store properties files created by the stormigrate utility at run-time. Additional recommended free disk space should be equivalent to 10 KB per device pair in each defined session.

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Files added during installThe following listed files are added during the installation:

/etc/opt/EMCom/etc/opt/EMCom/bin/etc/opt/EMCom/bin/stormigrate_11_00_32/etc/opt/EMCom/bin/stormigrate_11_00_64/etc/opt/EMCom/bin/stormigrate_11_11_32/etc/opt/EMCom/bin/stormigrate_11_11_64/etc/opt/EMCom/bin/omx_11_00_32/etc/opt/EMCom/bin/omx_11_00_64/etc/opt/EMCom/bin/omx_11_11_32/etc/opt/EMCom/bin/omx_11_11_64/etc/opt/EMCom/driver/etc/opt/EMCom/driver/emcom_11_00_32/etc/opt/EMCom/driver/emcom_11_00_64/etc/opt/EMCom/driver/emcom_11_11_32/etc/opt/EMCom/driver/emcom_11_11_64/etc/opt/EMCom/driver/drivers_emcom.tx/etc/opt/EMCom/driver/emcom.conf/etc/opt/EMCom/driver/master.emcom/etc/opt/EMCom/driver/system/etc/opt/EMCom/log/etc/opt/EMCom/properties/etc/opt/EMCom/properties/session.bounds,a/etc/opt/EMCom/properties/session.bounds,b/etc/opt/EMCom/properties/session.dfltparms,a/etc/opt/EMCom/properties/session.dfltparms,b/etc/opt/EMCom/properties/sessions,a/etc/opt/EMCom/properties/sessions,b/etc/opt/EMCom/share/etc/opt/EMCom/share/man/etc/opt/EMCom/share/man/man1/etc/opt/EMCom/share/man/man1/stormigrate.1/etc/opt/EMCom/share/man/man7/etc/opt/EMCom/share/man/man7/emcom.7

/dev/emcom

/sbin/stormigrate/sbin/init.d/emcom/sbin/init.d/emcom_resume

/stand/build/mod_wk.d/emcom/stand/build/mod_wk.d/emcom/_mod.o/stand/build/mod_wk.d/emcom/_mod_sec.o/stand/build/mod_wk.d/emcom/lmod.o/stand/build/mod_wk.d/emcom/mod.o/stand/build/mod_wk.d/emcom/mod_conf.c/stand/build/mod_wk.d/emcom/mod_conf.o


Installation

/stand/build/mod_wk.d/emcom/mod_sec.c/stand/build/mod_wk.d/emcom/mod_sec.o/stand/system.d/emcom/stand/dlkm/mod.d/emcom/stand/dlkm/system.d/emcom

/usr/conf/km.d/emcom/mod.o/usr/conf/master.d/emcom

/var/adm/sw/products/EMCom/var/adm/sw/products/EMCom/EMCom/var/adm/sw/products/EMCom/EMCom/INDEX/var/adm/sw/products/EMCom/EMCom/INFO

/var/adm/sw/products/EMCom/pfiles/var/adm/sw/products/EMCom/pfiles/INDEX/var/adm/sw/products/EMCom/pfiles/INFO/var/adm/sw/products/EMCom/pfiles/checkinstall/var/adm/sw/products/EMCom/pfiles/checkremove/var/adm/sw/products/EMCom/pfiles/configure/var/adm/sw/products/EMCom/pfiles/postinstall/var/adm/sw/products/EMCom/pfiles/postremove/var/adm/sw/products/EMCom/pfiles/preinstall/var/adm/sw/products/EMCom/pfiles/unconfigure

/var/EMCom/log/var/EMCom/lic

Note: Installation automatically creates binary links in the /sbin directory that point to the appropriate executable for your specific operating platform.

Session activationThe following is an example of an Open Migrator/LM session activation and the resulting properties files that are created:

# stormigrate create -session foo# stormigrate add -session foo /dev/vg1/rlv0 /dev/vg1/rlv1# stormigrate activate -session foo# ls -al /etc/opt/EMCom/properties

total 352drwxr-xr-x 2 root sys 8192Feb 7 16:01 .dr-xr-xr-x 8 bin bin 8192Feb 7 14:52 ..-rw-r--r-- 1 root sys 72 Feb 7 16:01 mvrcfg.FOO.t0000.m0000,a-rw-r--r-- 1 root sys 72 Feb 7 16:01 mvrcfg.FOO.t0000.m0000,b-rw-r--r-- 1 root sys 104 Feb 7 16:01 mvrstat.FOO.t0000.m0000,a


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Installation

-rw-r--r-- 1 root sys 104 Feb 7 16:01 mvrstat.FOO.t0000.m0000,b-rw-r--r-- 1 root sys 88 Feb 7 16:01 sesscfg.FOO,a-rw-r--r-- 1 root sys 88 Feb 7 16:01 sesscfg.FOO,b-rw-r--r-- 1 root sys 24 Jan 10 14:19 session.bounds,a-rw-r--r-- 1 root sys 24 Jan 10 14:19 session.bounds,b-rw-r--r-- 1 root sys 40 Jan 24 11:59 session.dfltparms,a-rw-r--r-- 1 root sys 40 Jan 24 11:59 session.dfltparms,b-rw-r--r-- 1 root sys 32 Feb 7 16:01 sessions,a-rw-r--r-- 1 root sys 32 Feb 7 16:01 sessions,b-rw-r--r-- 1 root sys 56 Feb 7 16:01 sessstat.FOO,a-rw-r--r-- 1 root sys 56 Feb 7 16:01 sessstat.FOO,b-rw-r--r-- 1 root sys 48 Feb 7 16:01 tskcfg.FOO.t0000,a-rw-r--r-- 1 root sys 48 Feb 7 16:01 tskcfg.FOO.t0000,b-rw-r--r-- 1 root sys 56 Feb 7 16:01 tskstat.FOO.t0000,a-rw-r--r-- 1 root sys 56 Feb 7 16:01 tskstat.FOO.t0000,b-rw-r--r-- 1 root sys 2144 Feb 7 16:01 volcfg.FOO.t0000,a-rw-r--r-- 1 root sys 2144 Feb 7 16:01 volcfg.FOO.t0000,b

Removing the software from HP-UXThis section describes how to remove the software from an HP-UX host. Follow the removal instructions for the version you are removing (v3.7 or v3.8 and later).

Removing Open Migrator/LM version 3.7 from HP-UXPerform the following steps to uninstall the Open Migrator/LM for UNIX software version 3.7 from a HP-UX host:


2. Ensure that all sessions have been deactivated by using the stormigrate deactivate command.

3. To remove the software, type:

swremove EMCom

The following directories and contents are retained on the host after removal of the software:

/etc/opt/EMCom/clirep/etc/opt/EMCom/log/etc/opt/EMCom/properties/var/emcom/log

Note: The /etc/opt/EMCom/clirep and /etc/opt/EMCom/log directories are only retained if they contain data. If empty of contents, they will be deleted when the software is removed.


Installation

4. Ensure that the directories noted in step 3 are manually deleted before attempting to install any new or previous version of Open Migrator/LM.

Note: Only remove the /var/emcom/log directory if you are completely finished using the product, as it contains necessary information used for troubleshooting.

Removing Open Migrator/LM versions 3.8 and later from HP-UXPerform the following steps to uninstall the Open Migrator/LM for UNIX software versions 3.8 and later from a HP-UX host:



3. Delete all defined sessions on the system to restore to a clean state by using the stormigrate cleanup command.


swremove EMCom


/etc/opt/EMCom/log/etc/opt/EMCom/properties/var/EMCom/log

Note: The /etc/opt/EMCom/log, /etc/opt/EMCom/properties and the /var/EMCom/log directories are only retained if they contain data. If empty of contents, they will be deleted when the software is removed.


Note: Only remove the /var/EMCom/log directory if you are completely finished using the product, as it contains necessary information used for troubleshooting.


36

Installation

Installing Open Migrator/LM on IBM AIXThis section describes how to install Open Migrator/LM for UNIX software on an IBM AIX host.

Note: If an existing version of Open Migrator/LM for UNIX software is currently installed, it must first be removed before installing another version. Refer to “Removing the software from IBM AIX” on page 38.

Perform the following steps to install the software on an IBM AIX host:


2. Copy the installation image .tar file to the /tmp directory and extract (untar) the .tar file. For example, type the following commands:

cp EMComlm.AIX.tar /tmpcd /tmptar -xvf EMComlm.AIX.tar


installp -ad . EMCom

Note: Refer to the installp man page for a list of optional flags.

The screen displays information about the installation, ending with the Installation Summary:

Installation SummaryName Level Part Event Result--------------------------------------------EMCom.base 3.10.0.0 USR APPLY SUCCESS

Note: If this is a reinstall, note that all of the previously set tuning option parameters (-ceiling, -iosize, -checkpointsize, -nthreads, -mio_perf_ratio, and -mio_recover_action) must be manually reset. Refer to “Tuning session performance” on page 66..


Installation

Disk space considerationsRecommended free disk space for installation on an IBM AIX host is 5 MB. In addition to the install footprint outlined in “Files added during install”, there should be sufficient space reserved in the /etc file system to store properties files created by the stormigrate utility at run-time. Additional recommended free disk space should be equivalent to 10 KB per device pair in each defined session.

Files added during installThe following files are added during the installation:

/dev/emcom0/etc/opt/EMCom/etc/opt/EMCom/bin/etc/opt/EMCom/bin/stormigrate_32/etc/opt/EMCom/bin/stormigrate_64/etc/opt/EMCom/bin/omload.sh/etc/opt/EMCom/bin/omx_32/etc/opt/EMCom/bin/omx_64/etc/opt/EMCom/log/etc/opt/EMCom/properties/session.bounds,a/etc/opt/EMCom/properties/session.bounds,b/etc/opt/EMCom/properties/session.dfltparms,a/etc/opt/EMCom/properties/session.dfltparms,b/etc/opt/EMCom/properties/sessions,a/etc/opt/EMCom/properties/sessions,b/etc/rc.emcom

/usr/lib/methods/cfgom/usr/lib/methods/ucfgom/usr/lib/methods/defom/usr/lib/methods/udefom/usr/lib/nls/msg/en_US/emcom.cat/usr/lib/drivers/emcom/usr/lib/drivers/emcom.conf/usr/sbin/stormigrate/usr/share/man/man1/stormigrate.1/usr/share/man/man7/emcom.7


Note: The /etc/inittab file will be modified by the installation.

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Installation

Note: For an example of an Open Migrator/LM session activation, refer to “Session activation” on page 33.

Note: Installation automatically creates binary links in the /usr/sbin directory that point to the appropriate executable for your specific operating platform.

ODM modifications The following ODM modifications are caused by the install:

Additions to PdDv and CuDv for emcom0 control device.Addition of Config_Rule to configure software after a reboot.

Removing the software from IBM AIXThis section describes how to remove the software from an IBM AIX host. Follow the removal instructions for the version you are removing (v3.7 or v3.8 and later).

Removing Open Migrator/LM version 3.7 from IBM AIXPerform the following steps to uninstall the Open Migrator/LM for UNIX version 3.7 software from an IBM AIX host:




installp -u EMCom

The screen displays information about the uninstall, ending with the Installation Summary:

Installation SummaryName LevelPartEventResult------------------------------------------------EMCom.base3.7.0.0USRDEINSTALLSUCCESS




Installation




Removing Open Migrator/LM versions 3.8 and later from IBM AIXPerform the following steps to uninstall the Open Migrator/LM for UNIX software versions 3.8 and later from an IBM AIX host:



3. Delete all sessions and associated log files on the system to restore to a clean state by using the stormigrate cleanup command.


installp -u EMCom

The screen displays information about the uninstall and ends with the Installation Summary:

Installation SummaryName LevelPartEventResult------------------------------------------------EMCom.base3.8.0.0USRDEINSTALLSUCCESS




Installing Open Migrator/LM on IBM AIX 39

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Installation




Installation

Installing Open Migrator/LM on Sun SolarisThis section describes how to install Open Migrator/LM for UNIX software on a Sun Solaris host.

Note: If an existing version of Open Migrator/LM for UNIX software is currently installed, it must first be removed before installing another version. Refer to “Removing the software from Sun Solaris” on page 43.

Perform the following steps to install Open Migrator/LM on a Sun Solaris host:


2. Copy the installation image .tar file to the /tmp directory. For example, type the following commands:

cp EMComlm.SUN.tar /tmpcd /tmptar -xvf EMComlm.SUN.tar

3. Change directories to the directory on the installation media that contain the package appropriate for your system:

cd /tmp/system

where system is 580, 590 or 510, for Solaris 8, 9 and 10, respectively.


pkgadd -d .


Disk space considerationsRecommended free disk space for installation on a Sun Solaris host is 5 MB. In addition to the install footprint outlined in “Files added during install” on page 42, there should be sufficient space reserved in the /etc file system to store properties files created by the stormigrate utility at run-time. Additional recommended free disk

Installing Open Migrator/LM on Sun Solaris 41

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Installation

space should be equivalent to 10 KB per device pair in each defined session.

Files added during installThe following files are added during the installation:

/etc/opt/EMCom/bin/sparcv8/stormigrate/etc/opt/EMCom/bin/sparcv8/omx/etc/opt/EMCom/bin/sparcv9/stormigrate/etc/opt/EMCom/bin/sparcv9/omx/etc/opt/EMCom/man/man7d/emcom.7d/etc/opt/EMCom/man/man7d/stormigrate.1m/etc/opt/EMCom/module/adddrv.ksh.EMCom/etc/opt/EMCom/module/addrcinit.ksh.EMCom/etc/opt/EMCom/module/addsymlink.ksh.EMCom/etc/opt/EMCom/module/remdrv.ksh.EMCom/etc/opt/EMCom/module/remrcinit.ksh.EMCom/etc/opt/EMCom/module/remsymlink.ksh.EMCom/etc/opt/EMCom/module/init.ksh.EMCom/etc/opt/EMCom/properties/session.bounds,a/etc/opt/EMCom/properties/session.bounds,b/etc/opt/EMCom/properties/session.dfltparms,a/etc/opt/EMCom/properties/session.dfltparms,b/etc/opt/EMCom/properties/sessions,a/etc/opt/EMCom/properties/sessions,b/etc/rc2.d/S86emcomrc.ksh

/kernel/drv/emcom/kernel/drv/emcom.conf/kernel/drv/sparcv9/emcom

/usr/sbin/stormigrate



Note: Installation automatically creates binary links in the /usr/sbin directory that points to the appropriate executable for your specific operating platform as follows: /etc/opt/EMCom/bin/sparcv8 for 32 bit kernel or /etc/opt/EMCom/bin/sparcv9 for 64 bit kernel.


Installation

Removing the software from Sun SolarisThis section describes how to remove the software from a Sun Solaris host. Follow the removal instructions for the version you are removing (v3.7 or v3.8 and later).

Removing Open Migrator/LM version 3.7 from Sun SolarisPerform the following steps to uninstall the Open Migrator/LM for UNIX version 3.7 from a Sun Solaris host:




pkgrm EMCom






Note: Under certain conditions the kernel module could have busy text, in which case the software cannot be removed unless the daemon processes are stopped. Refer to “Stopping daemon processes” on page 45 for further instructions.


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Installation

Removing Open Migrator/LM versions 3.8 and later from Sun SolarisPerform the following steps to uninstall the Open Migrator/LM for UNIX software versions 3.8 and later from a Sun Solaris host:





pkgrm EMCom







Installation

Stopping daemon processesUnder certain conditions the kernel module could have busy text, in which case the software cannot be removed unless the daemon processes are stopped. For instance, if the Volume Management daemon vold(1M) has made a blocking call ioctl(2) to monitor removable media events in floppy disks or CD-ROM drivers, the vold(1M) daemon must be manually stopped. The software can then be removed, and then the daemon can be restarted. This will allow the software to be removed without requiring a system reboot.

Note: Refer to your Sun Solaris package documentation for information regarding the availability of specific commands that can be used to collect and sort out process kernel stack traces to detect running daemon processes, which may cause the package remove command to fail.


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Installation

Installing Open Migrator/LM on LinuxThis section describes how to install Open Migrator/LM for Linux software on a Red Hat Enterprise Linux AS host.

Please refer to Open Migrator/LM in E-Lab Navigator at http://Powerlink.EMC.com for supported platform and kernel version information prior to attempting installation. You should also refer to your EMC Open Migrator/LM for UNIX and Linux Version 3.10 Release Notes for specific environment and system requirements.

Note: Accessed from the Powerlink home page, move the cursor over the Support > Interoperability/Compatibility/Configuration > E-Lab Interoperability Navigator, and click Launch E-Lab Interoperability Navigator.

Note: If an existing version of Open Migrator/LM for Linux software is currently installed, it must first be removed before installing another version. Refer to “Removing the software from Linux” on page 48.

Perform the following steps to install Open Migrator/LM on a Linux host:


2. Copy the installation image .tar file to the /tmp directory and extract (untar) the .tar file. For example, type the following commands:

cp EMComlm.LINUX.tar /tmpcd /tmptar -xvf EMComlm.LINUX.tar


rpm --install EMCom-V3.10.0.xx-rhel-3-i386.as.rpm

(Where x is the actual version number)



Installation

Disk space considerationsRecommended free disk space for installation on a Linux host is 5 MB. In addition to the install footprint outlined below, there should be sufficient space reserved in the /etc file system to store properties files created by the stormigrate utility at run-time. Additional recommended free disk space should be equivalent to 10 KB per device pair in each defined session.

Note: Systems must be configured with at least 1 GB of physical memory to load the kernel module.

Files added during installThe following listed files are added during the installation:

/etc/opt/EMCom/etc/opt/EMCom/bin/etc/opt/EMCom/omx/etc/opt/EMCom/bin/stormigrate/etc/opt/EMCom/driver/etc/opt/EMCom/driver/emcom.conf/etc/opt/EMCom/driver/emcom_hugemem/etc/opt/EMCom/driver/emcom_smp/etc/opt/EMCom/driver/emcom_up/etc/opt/EMCom/driver/drivers_emcom.tx/etc/opt/EMCom/log/etc/opt/EMCom/man/etc/opt/EMCom/man/man4/etc/opt/EMCom/man/man4/emcom.4.gz/etc/opt/EMCom/man/man8/etc/opt/EMCom/man/man8/stormigrate.8.gz/etc/opt/EMCom/properties/etc/opt/EMCom/properties/session.bounds,a/etc/opt/EMCom/properties/session.bounds,b/etc/opt/EMCom/properties/session.dfltparms,a/etc/opt/EMCom/properties/session.dfltparms,b/etc/opt/EMCom/properties/sessions,a/etc/opt/EMCom/properties/sessions,b/etc/opt/EMCom/scripts/etc/opt/EMCom/scripts/addmod.sh/etc/opt/EMCom/scripts/addrcinit.sh/etc/opt/EMCom/scripts/addsymlink.sh/etc/opt/EMCom/scripts/copyright.emc/etc/opt/EMCom/scripts/initdb.sh/etc/opt/EMCom/scripts/remmod.sh/etc/opt/EMCom/scripts/remrcinit.sh/etc/opt/EMCom/scripts/remsymlink.sh

Installing Open Migrator/LM on Linux 47

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Installation

/var/EMCom/lic/var/EMCom/log


Removing the software from LinuxPerform the following steps to uninstall the Open Migrator/LM for Linux versions 3.8 and later software from a Red Hat Enterprise Linux AS host:





rpm -qa|grep EMCom

Note: This entry returns the version number to be inserted in the next line (for example: EMCom-V3.10.0.1.1).

rpm --erase EMCom-<insert version #>





Installation



Installing Open Migrator/LM on Linux 49

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3Invisible Body Tag

This chapter provides instructions for using the Open Migrator/LM stormigrate command to manage data migration and comparison operations between data volumes.

◆ Session overview................................................................................ 52◆ Control operations ............................................................................. 54

Open Migrator/LMControl Operations

Open Migrator/LM Control Operations 51

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Open Migrator/LM Control Operations

Session overviewData migration and comparison operations that use the stormigrate command are performed from a production host and are completed in sessions. Volume pairs consisting of source and target devices can be located on the same array or separate arrays. A device file can be used to specify a list of the volume pairs for the operation at the time the session is created, or pairs can be added to the session after it is created. The production host for the kernel driver must have access to the volumes for the session, and is responsible for controlling data migration between the volume pairs.

A session is first defined by using the stormigrate create command and specifying a session name. An additional option parameter (-file) can be used to define volume pairs by attaching a separate device file to the create command. Volume pairs listed in the device file can be identified by:

◆ physical device name (for example, /dev/rvol2)

◆ raw disk name (for example, /dev/rdsk/c1t1d3s2)

◆ database application volume pathname (for example, /dev/emc/ora3_tgt_9/rvol6).

Refer to “Creating a device file” on page 54 for instructions on how to create a device file for the session.

Note: With the exception of character devices of the raw(8) driver, Open Migrator/LM for Linux does not support character devices (rdsk).

Migrating data between storage arraysRefer to Figure 3 for a depiction and syntax example of an Open Migrator/LM session that has been created, activated, and is currently copying (migrating) data between the source and target volumes.

A device file (-file devpairfile) titled volume_pairs contains the pairing information for the source and target volumes. Volumes are specified by the raw disk and volume pathnames as follows:

/dev/rdsk/c3t0d44s2 /dev/rdsk/c4t0d22s2/dev/vx/rdsk/ora1_src_vg/rvol1 /dev/vx/rdsk/ora1_tgt_vg/rvol1/dev/ora2_src_vg/rvol2 /dev/ora2_tgt_vg/rvol2



Figure 3 Data migration using the stormigrate command

Data Migration

Copy Session

StorageArray 2

Volumec4t0d22s2



StorageArray 1


Volumec3t0d44s2


Application

EMC Open Migrator/LM

Device Control

SourceDevices

TargetDevices

Data Migration

ProductionHost

stormigrate create -session session1 -file volume_pairsstormigrate activate -session session1stormigrate copy -session session1

{ {

Session overview 53

54


Control operationsThe stormigrate command allows you to perform Open Migrator/LM control operations on a collection of volumes in a session. By using this command, you can do the following:

◆ Create a session to migrate or compare data between storage arrays.

◆ Add source and target volumes to a created session.

◆ Activate or deactivate a session.

◆ Pause or resume the copying or comparing of a session.

◆ Restart a failed session.

◆ Tune session performance at the kernel level.

◆ List, query, show, and verify sessions for current status.

◆ Set frequently used environmental variables.

◆ Delete a session.

◆ Clean up old session data to restore system to a clean state.

◆ Display session properties.

Note: For detailed syntax of the stormigrate command, refer to Appendix A, “Command Reference,”.

Creating a device fileBefore creating a session, you can create a device file that contains a list of the source and target volume pairs for the operation. The device file must contain two columns (one for source devices and one for target devices) separated by spaces or tabs. Volumes listed in the device file can be specified either by their unique physical device name (for example, /dev/rvol2), raw disk name (for example, /dev/rdsk/c16t0d1), or database application volume pathname (for example, /dev/emc/ora3_tgt_9/rvol6).

Following is an example of various source and target volume pairing names:

/dev/rdsk/c16t0d0 /dev/emc/rdsk/ora1_tgt_9/vol4/dev/rdsk/c16t0d1 /dev/emc/rdsk/ora2_tgt_9/vol5/dev/rdsk/c16t0d2 /dev/emc/ora3_tgt_9/rvol6



/dev/ora4_src_9/rtpcb01_src_9 /dev/rvol16/dev/vx/rdsk/ora2_src_2/vol11 /dev/rvol2

Note: With the exception of character devices of the raw(8) driver, Open Migrator/LM for Linux does not support character devices (rdsk).

The source volume must always be listed in the first column of the device file. Lines in the device file that begin with a pound sign (#) will be ignored. The device filename (-file devpairfile) will be inserted into the command line for control operations.

If the device file contains blank lines, do not include spaces or tabs on that line. When the file is input to create the session, if spaces or tabs are encountered on a blank line, the following error message returns: "No source filespec on line x" (where x is the line number). This is because the line is not really empty and the parser expects a device name to be specified on that line.

Note: The file containing the device pair information cannot be empty. Comment lines must be preceded with a pound sign (#).

A device text file that lists pairs of source and target volumes is shown in the following example.

Example of a device file

Although the above example shows device pairs that migrate data from one distinct volume group to another volume group, this is not a requirement. Open Migrator/LM can be used to migrate data from source to target volumes within the same volume group or between separate volume groups.

# file name: volume_pairs_1# source and target volume pairs for migration session1# first column lists source devices# second column lists target devices# BEGIN/dev/ora1_src/rvol1 /dev/vx/rdsk/ora1_tgt/vol1/dev/vx/rdsk/ora2_src/vol2 /dev/ora2_tgt/rvol2/dev/ora3_src/rvol3 /dev/ora3_tgt/rvol3#/dev/vx/rdsk/ora4_src/tpcb01 /dev/vx/rdsk/ora4_tgt/tpcb01/dev/vx/rdsk/ora4_src/tpcb02 /dev/vx/rdsk/ora4_tgt/tpcb02/dev/vx/rdsk/ora4_src/tpcb03 /dev/vx/rdsk/ora4_tgt/tpcb03/dev/vx/rdsk/ora4_src/tpcb04 /dev/vx/rdsk/ora4_tgt/tpcb04/dev/vx/rdsk/ora4_src/tpcb05 /dev/vx/rdsk/ora4_tgt/tpcb05# END

Control operations 55

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Note: If a new target volume group has been created for migrating logical volume data to, it is recommended that you export the original volume group and then import the new volume group with the same name as the original. The import and export should be done after the data has been migrated and validated for completion.

Guidelines for choosing volume pairsWhen choosing your source and target volumes for a copy session, use the following guidelines:

◆ If possible, choose source volumes that are closest to the application layer in the I/O stack. Refer to “I/O stack layers” on page 23 for an explanation of the I/O stack layers.

◆ Choose target volumes that are not already mounted.

◆ Ensure that the target volume is of the same size or larger than the source volume.

◆ If the storage environment includes additional hosts that have access to the target volume, set the target volume as not ready to those hosts.

◆ With the exception of character devices of the raw(8) driver, Open Migrator/LM for Linux does not support character devices. The software checks that character devices named in add and create commands are raw(8) driver character device special file nodes.

◆ A device pair cannot be added to a session if either of the devices in the device pair is part of another session that is active.

Note: When choosing target volumes within a Solaris environment, if devices are previously unused devices, they should be labeled.

Provisioning target volumesTarget volumes must be provisioned at the level in the I/O stack layer where the data will be accessed by the application after the migration has completed. If target volumes are logical volumes, the target volumes must be created and made ready for data access by Open Migrator/LM prior to creating the session. This is accomplished by using the volume manager’s administrative tools. For an explanation of the I/O stack layers within a UNIX/Linux OS kernel, refer to “I/O stack layers” on page 23.



Creating a sessionA session is first created by using the stormigrate create command to define a new session. The -session name option is used to define the session name. Optionally, you can specify a device text filename (-file devpairfile) that contains volume pairs for the operation. Refer to “Creating a device file” on page 54 for instructions on how to create the device file.

The session can be used to migrate data or to compare data on specific volumes. A session name is defined when creating the session. The session name can be any alphabetical or numeric character and cannot exceed 32 characters in length. Once the session has been created, volume pairs can be added to populate the session or additional pairs can be included beyond those identified in the device file. To define a session by using the stormigrate command for a device pair file, use the following example:

stormigrate create -session session1 -file volume_pairs_1

In the above example, the name of the session is identified as session1. The name of the device text file to be used for the session is specified as volume_pairs_1.

Note: With the exception of character devices of the raw(8) driver, Open Migrator/LM for Linux does not support character devices. The software checks that character devices named in add and create commands are raw(8) driver character device special file nodes.

Skipping the label sector on Sun SolarisWhen planning migrations for Sun Solaris systems, it is important to consider the possible presence of the Solaris disk label. If migrating to a target volume that includes a disk label sector, the application must share the space on the volume occupied by the disk label with the operating system. Because the Solaris default partitions s0 and s2 include a disk label sector, which is addressable by application programs, including Open Migrator/LM, they are vulnerable to being overwritten.

CAUTION!The consequences of overwriting a disk label can include data loss or data corruption.


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If creating a session or adding devices to a session on a Sun Solaris host, you may need to skip the sector of the device that contains the device label (disk label block) during the migration process. Generally, the first cylinder (cylinder 0) contains the device label. Open Migrator/LM can detect session configurations that would result in an overwrite of the disk label on a SCSI target volume and will prompt the user to reissue either the create or add command to include the -skip_label_sector or -noskip_label_sector option to make any overwrite intentional.

If disks are formatted with Solstice Disk Suite or Solaris Logical Volume Manager meta device disk partitions, you can use the -skip_label_sector option with the stormigrate create or add commands to exclude the label sector of the source metadevice from being copied to the target.

In Open Migrator/LM session configurations that include Solstice Disk Suite metadevices (md) 7 driver volumes, the md(7) driver will refuse any write request to the target volume disk label sector made by Open Migrator/LM. Without soft partitions or disk sets, the Solstice Disk Suite metadevice driver attempts to write to cylinder 0 of the target device, causing a target write error.

Open Migrator/LM performs a device validation process to determine if partitions s0 and s2 include a disk label sector. During this process, a notice is generated and logged by the Sun Solaris operating system with the device number (for example, "NOTICE: md:d13; write to label"). Note that despite the reporting of this operating system notification, no data was actually written to the disk label.

For Solstice one-on-one concatenated volumes, EMC recommends always including the -skip_label_sector option to avoid attempting to migrate the disk label block.

To include the disk label block to be copied in the migration, use the -noskip_label_sector option.



Table 2 shows the various device configurations for source and target devices including VTOC blocks, lists whether or not a warning message is generated, and describes any applied default action.

Note: EMC recommends including the -skip_label_sector option when you do not want the disk label block on the target to be overwritten.

For example, if you are migrating from a Solaris UFS partition without a disk label block (such as partition s3) to a Solaris UFS on partition cxtxdxs0 or s2, the -skip_label_sector option will ensure that the target device is still accessible. If you use -noskip_label_sector option, the target's disk label block would be overwritten, rendering the data inaccessible.

Likewise, if you were migrating from a partition with a disk label block to another partition with a disk label block (such as s2 to s2), you probably do not want to overwrite the target partition's label with the label from the source, so the -skip_label_sector option is the appropriate choice.

Note: If the device pairs to be migrated contain a mix of devices (some with a disk label block and some without), it is recommended that you do not include the devices within the same device file. This is because the -skip_label_sector and the -noskip_label_sector command options act globally on all device pairs contained within the device file.

Table 2 Open Migrator/LM use with VTOC blocks

Source device Target device Warning Default action

No disk label block No disk label block No -noskip_label_sector

No disk label block Disk label block Yes User decidesa

Disk label block No disk label block No -noskip_label_sector

Disk label block Disk label block Yes User decidesa

a. It is the user’s responsibility to decide whether to intentionally overwrite the disk label sector on the target device.


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Adding devices to a sessionThe stormigrate add command is used to associate volume pairs with a session. Volume pairs can be associated with a session in addition to those volumes that may have been defined with a device file at the time the session was created. The session must first be deactivated to associate volume pairs by using the add command. The source device is always listed first, followed by the target device.

To associate volume pairs with a session, use the following example:

stormigrate add -session session1 /dev/rdsk/c3t0d50s2 /dev/rdsk/c4t0d28s2stormigrate add -session session1 /dev/rdsk/c3t0d51s2 /dev/rdsk/c4t0d29s2stormigrate add -session session1 /dev/vx/rdsk/src_vg/vol3 /dev/vx/rdsk/tgt_vg/vol3

In the above example, three additional volume pairs were added to the session (session1). Volume pairs can be defined by either physical device name, database application volume pathname, or raw disk name as shown

Note: Using the stormigrate add command to add additional volume pairs does not modify the existing device file.

Note: The session must be activated before the kernel driver can establish the session for a copy or compare command action.

Note: A device pair cannot be added to a session if either of the devices in the device pair is part of another session that is active.

Note: With the exception of character devices of the raw(8) driver, Open Migrator/LM for Linux does not support character devices. The software checks that character devices named in add and create commands are raw(8) driver character device special file nodes.

If adding devices on a Sun Solaris host, refer to “Skipping the label sector on Sun Solaris” on page 57.



Listing sessions You can list all of the currently defined sessions by using the stormigrate list command. This command returns status information for each session created from the operating host. The following example of the stormigrate list command displays a list of four current session names and their state.

stormigrate list

Session State-----------------------session1 Inactivesession2 Inactivesession3 Activesession4 Active

4 sessions found.

Showing session data You can display session configuration information for a specific session by using the stormigrate show command and specifying the session name. The following example displays the output from the stormigrate show -session command.

stormigrate show -session session1

MBSource Size Target ---------------------- ------ -----------------------/dev/rdsk/c3t0d44s2 10780 /dev/rdsk/c4t0d22s2/dev/rdsk/c3t0d45s2 10780 /dev/rdsk/c4t0d23s2/dev/rdsk/c3t0d46s2 10780 /dev/rdsk/c4t0d24s2/dev/rdsk/c3t0d47s2 10780 /dev/rdsk/c4t0d25s2/dev/rdsk/c3t0d48s2 10780 /dev/rdsk/c4t0d26s2/dev/rdsk/c3t0d49s2 10780 /dev/rdsk/c4t0d27s2/dev/rdsk/c3t0d50s2 10780 /dev/rdsk/c4t0d28s2/dev/rdsk/c3t0d51s2 10780 /dev/rdsk/c4t0d29s2*x/rdsk/src_vg/vol3 35920 *x/rdsk/tgt_vg/vol3

Session Name: session1Session State: ActiveAction Plan: CopyTask States: RunningNumber of Pairs: 9Total Source Size: 122160


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Note: By default, source and target volume pathnames that are too long for the display are truncated to the left of the name. Truncated pathnames are identified by an asterisk (*) in the first character space. Use the -v option to display the complete pathname.

Note: Including the -summary option will display only the session summary data.

Activating a sessionThe stormigrate activate command is used to activate a session. When a session is activated, it becomes established in the kernel driver under the defined session name. To activate a session, one or more volume pairs (source/target) must have been previously added to the session or defined in a device file at the time the session was created.

To activate a session, use the following example:

stormigrate activate -session session1

Note: Target volumes should not be mounted when the session is activated.

Note: Once a session has been activated, target volumes for the session will not be visible to the host operating system disk managers (for example, Solaris format utility, HP-UX SAM) or other third party disk polling software (for example, syminq) until the session has been deactivated.

Deactivating a session To deactivate a session and remove it from the kernel driver, use the stormigrate deactivate command and specify the session name.

To deactivate a session, use the following example:

stormigrate deactivate -session session1

Note: Information for a session will be retained until the session is deleted.



Start device copyingTo begin volume copying for an activated session, use the stormigrate copy command. The copy command begins the transfer of data between the source and target devices associated with the session. The session must be activated before copying can begin. To begin transferring data from the source to target devices, use the following example:

stormigrate copy -session session1

Data copying operations are processed in the kernel driver for each task comprised in the session. When all subsequent copy tasks have completed, session volumes continue to be mirrored for as long as the session remains in an activated session state. You can check the session status for copy completion by using the stormigrate show, query or verify commands.

During copy operations, source volumes remain operational for I/O to its host and target volumes are read/write disabled. Target volumes should also be set as not ready to any additional attached hosts with access to volumes.

You can use the stormigrate query command to monitor the transfer copy rate of a session. The transfer copy rate by default is set to 1Mb/s. This transfer rate can be adjusted by setting the stormigrate tune -ceiling value. Refer to “Setting the target bandwidth” on page 66 for instructions.

Pausing the sessionA session that is currently copying or comparing data can be paused to temporarily stop task processing and can later be resumed from the point where it was paused. This feature can be useful if it becomes necessary to conserve system resources by resuming data copying at a later time.

Additionally, from a paused state, you may choose to change the action state from a compare operation to begin copying or vice versa from the beginning of the session. Refer to “Forcing a copy or compare action” on page 64.

To pause an active session to temporarily stop task processing, use the following example:

stormigrate pause -session session1


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When a session is paused, all tasks for the identified session in the kernel driver are suspended at their current data volume offsets and saved.

Resuming the sessionResuming a paused session causes the kernel driver to continue any task from its paused data volume offsets. To resume a paused session, use the following example:

stormigrate resume -session session1

If the session was copying data when it was paused, the resume command will continue the copying of data from the point where it was paused.

Forcing a copy or compare action When a session is in a paused state, you may change the action to begin a copy or compare action from the beginning of the session. For example, to force a session to begin copying from the source to target devices from the beginning of the session, use the following example:

stormigrate copy -force -session session1

Alternately, you may choose to begin a compare operation to compare source and target data. The following example will force the session to begin a compare action between the source and target devices in the session.

stormigrate compare -force -session session1

CAUTION!Forcing a compare action on a session that was paused while actively copying could result in an incomplete volume copy between some or all source and target volumes in the session.



Deleting a sessionTo delete an existing session and remove it from the kernel driver, use the stormigrate delete command. If the session is currently activated, you must include the -force option to stop session tasks and force the deletion of the session. To delete an active session, use the following example:

stormigrate delete -session session1 -force

CAUTION!Forcing the deletion of an active session could result in an incomplete volume copy between some or all source and target volumes in the session.

Note: When migration completes, the session information can be preserved or deleted. You can preserve the session information by only deactivating the session.

Restarting a failed sessionA failed session can be restarted by using the stormigrate restart command to resume session tasks in the kernel driver from the beginning data volume offsets. Any failed session tasks with an error status or Mirror I/O Throttling (MIOT) status will begin operations again. To restart a failed session, use the following example:

stormigrate restart -session session1

Note: A restart operation should only be done after all other tasks in the session have completed.

Note: For information on MIOT status, refer to “Setting the write performance ratio for mirrored pairs” on page 68.


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Tuning session performanceThe system parameters for sessions can be tuned at the kernel level by using the stormigrate tune command. Tuning the session system parameters allows you to set data migration rates by adjusting the impact of I/O loading and mirroring performance. The tune command can be used to preserve system bandwidth for data migration during peak hours of operation. To view the tune parameters currently in effect, specify the tune command without any options. The tune command includes the following options: -iosize , -ceiling, -checkpointsize, -nthreads, -mio_perf_ratio, and -mio_recover_action.

Setting the I/O buffer sizeYou can set the input/output buffer size (in kilobytes) to be used for data transfers in a session by using the -iosize option. Values can range from 64 K to 128 K. The default setting is 64 K. Use the following example to set the I/O transfer buffer rate:

stormigrate tune -iosize 128

Note: Parameter changes made with the -iosize command affect only new sessions that have not yet been activated in the kernel driver.

Note: The parameter setting for the -iosize option must be reset in the event that the Open Migrator/LM software is removed and reinstalled.

Setting the target bandwidthYou can set the operating bandwidth (in megabytes) for target devices in all sessions by using the -ceiling option. Setting the bandwidth allows the software to throttle all data transfer operations so that the aggregate bandwidth remains at or below the set ceiling value. Values can range from 1 to 10,000 megabytes per second, depending on your system, with the default value being 1 MB.

To set the operating bandwidth for all sessions to 30 MB, type:

stormigrate tune -ceiling 30

You can set the maximum allowed bandwidth for your system by using the max qualifier. This will apply the maximum amount of bandwidth available for your system to all sessions.



Note: Setting the ceiling parameter to max may impact the performance of other programs running on the system.

Note: Refer to “Application performance considerations” on page 25 for additional information regarding I/O load and user application response time when setting the ceiling parameter.

To set the maximum allowed bandwidth for your system, type:

stormigrate tune -ceiling max

Note: Parameter changes made with the -ceiling option take effect immediately for all running sessions and will be in effect for all sessions that have not yet been activated in the kernel driver.

Note: The parameter setting for the -ceiling option must be reset in the event that the Open Migrator/LM software is removed and reinstalled.

Setting the property records update intervalYou can set the interval (in megabytes) at which the data mover’s property records are updated by using the -checkpointsize option. Setting this value allows you to control the frequency of the data mover’s data transfer offsets between updates to the task’s properties records. Values can range from 32 to MAXINT. The default value is 256. Setting the value to NONE indicates that the data movers will only update the properties records for a final status update. This parameter can be updated at any time and will have an immediate effect.

To set the update interval for property records for all sessions to 128 MB, type:

stormigrate tune -checkpointsize 128

To indicate that property records only be updated for a final status, type:

stormigrate tune -checkpointsize none

Note: Parameter changes made with the -checkpointsize option take effect immediately for all running sessions and will be in effect for all sessions that have not yet been activated in the kernel driver.


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Note: The parameter setting for the -checkpointsize option must be reset in the event that the Open Migrator/LM software is removed and reinstalled.

Setting the number of data mover threadsYou can set the size of the kernel module’s number of available threads that are used to process data mover tasks by using the -nthreads option. Setting this value allows you to control how many data mover threads are available in a fixed size cache allocated from the operating system. The value can be set from 1 to 64. The default value is 16. This parameter can be updated at any time and will have an immediate effect if increased. If the number of threads is decreased, the effect may be deferred until threads are idled. You may temporarily pause a session by using the stormigrate pause and resume commands to effectively idle the threads.

Open migrator tasks are queued for available thread use. Tasks are added to the queue in the order that they appear in their session definition. Once a thread is associated with a task, the association lasts until the task completes its action (copy or compare) or until the task is interrupted by a delete or pause command. When a task completes or is paused, its thread is returned to the cache and made available to any task waiting for an available thread. Sessions are added to the queue in the order in which they are activated.

To set the number of available data mover threads to 32, type:

stormigrate tune -nthreads 32

Note: Parameter changes made with the -nthreads option take effect immediately for all running sessions and will be in effect for all sessions that have not yet been activated in the kernel driver.

Note: The parameter setting for the -nthreads option must be reset in the event that the Open Migrator/LM software is removed and reinstalled.

Setting the write performance ratio for mirrored pairsThis feature (also called Mirror I/O Throttling or MIOT for short) provides you the capability to set the write performance ratio between mirrored pairs, in order to lesson the impact of operating with a slower target device.

The performance ratio is the maximum allowable difference for operation between mirrored volumes in device pairs. The set ratio



can range between 110 percent and 500 percent. A default value of 200 percent allows Open Migrator to tolerate copying and mirroring to target devices that are one half the speed of the source device.

You set the write performance ratio for mirrored pairs by using the -mio_perf_ratio option. This option works in conjunction with the recovery action option (-mio_recover_action), which allows you to apply a specific course of action if the ratio threshold is exceeded. Refer to “Setting a recovery action for mirrored pairs” below for more information.

If the operating threshold on some device pairs in an activated session are exceeded, then the copy, compare, or mirroring operation of those pairs can be terminated and the operation restarted at another time.

To set the performance ratio (MIOT) to 200 percent, type:

stormigrate tune -mio_perf_ratio 200

Note: Parameter changes made with the -mio_perf_ratio option take effect immediately for all running sessions and will be in effect for all sessions that have not yet been activated in the kernel driver.

Note: The parameter setting for the -mio_perf_ratio option must be reset in the event that the Open Migrator/LM software is removed and reinstalled.

For information on how to check the current MIOT performance ratio of device pairs in a session, refer to “Displaying performance statistics” on page 74.

Setting a recovery action for mirrored pairsYou can set a course of action for device pairs in a session that exceed the set performance ratio (-mio_perf_ratio) by using the (-mio_recover_action) option. The value can be set to either ignore, log, or terminate. If set to ignore, no action is taken. If set to log, a warning message is written to the system log. If set to terminate and Open Migrator is actively copying or comparing, the action is suspended but mirroring continues. If set to terminate and Open Migrator is only mirroring, the mirroring will be disabled. The default setting is terminate.

When the threshold set in the -mio_perf_ratio has been exceeded while copy or compare operations are active, the task state for the affected device pair changes to MIOT1. The copy or compare task


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data mover is suspended, stopping the copy or compare action but continuing to mirror data. When the set threshold has been exceeded while copy or compare operations are not active, the task state for the affected device pair changes to MIOT2. The I/O mirroring function for the device pair is disabled. After all other session tasks have completed, the stormigrate restart command may be used to continue the session for incomplete MIOT tasks. All MIOT control events are recorded to the system log for future reference.

To set the MIOT recovery action for device pairs to log warning messages to the system log, type

stormigrate tune -mio_recover_action log

Note: Parameter changes made with the -mio_recover_action option take effect immediately for all running sessions and will be in effect for all sessions that have not yet been activated in the kernel driver.

Note: The parameter setting for the -mio_recover_action option must be reset in the event that the Open Migrator/LM software is removed and reinstalled.

Table 3 MIOT task state table

MIOT state encountered During task operation MIOT effect Upon restart operation

MIOT1 Copy • Copying suspended• Mirroring continues

• Mirroring continues• Copying resumes from

point of suspension

MIOT2 Copy • Copying and mirroring suspended

• Copying and mirroring resumes from beginning of the volume

MIOT1 Compare • Compare suspended• Mirroring continues

• Mirroring continues• Compare resumes from

point of suspension

MIOT2 Compare • Compare and mirroring suspended

• Mirroring restarts• Copying restarts from

beginning of volume• When copying is complete,

compare restarts from the beginning of volume

• Mirroring continues



Checking for MIOT task statesIt is important that you query all sessions for existing MIOT task states immediately before committing the migrated data. Note that active sessions which have completed copying and are left in a mirroring state could still encounter the MIOT task state. When all other session tasks have completed, you may use the stormigrate restart command to continue the session for incomplete MIOT tasks.

To check the status of device pairs for tripped MIOT task states, use the stormigrate query command as shown in the following example.

stormigrate query -session session1 S D y o Current Task n Rate n KBSource Target Action State c KB/s % e Left----------------------- ----------------------- -------- ----- - ---- --- -------/dev/rdsk/c3t2d37s2 /dev/rdsk/c3t2d38s2 Copy MIOT1 N 0 1 4358144 ---- --- -------Total Copy: 0 1 4358144Total Compare: 0 0 0

Session Name: 123Session State: ActiveAction Plan: CopyTask States: MIOTMoverSuspendedNumber of Pairs: 1Total Source Size: 4417920 KBSystem I/O Processing: MIRRORINGTarget Devices State: NRTime: 14:45:23

Warning: Mirror I/O throttling (MIOT) controls have beenapplied to tasks of this session. The task state MIOT1indicates that MIOT has suspended the task data mover.The task state MIOT2 indicates that MIOT has disabled thetask I/O mirroring function. The restart command may beused to continue this session. Check system logs forMIOT control event notifications. Refer to the productdocumentation for more information concerning MIOT.

The above example shows that the device pair in session1 has tripped the MIOT1 task state and that the data mover for the task has been suspended.


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Verifying session statesYou can use the stormigrate verify command to poll for the completion status of an activated session. The command returns completion status information once, or in intervals (-i) for a defined count (-c). If the session encounters an error, the command returns a non-zero exit code. To poll the session status every 60 seconds for a total of 10 times, use the following example:

stormigrate verify -session session1 -int 60 -c 10

The session status information displayed will state whether the copy or compare operation has been completed.

Note: If the (-c) option is not specified and an interval (-i) is specified, the program continuously displays status information until the session either completes or returns an error status.



Querying session statusTo query the status of a kernel driver session, use the stormigrate query command. Optionally, the session can be queried in intervals (-i) for a specified count (-c).


stormigrate query -session session1

s Dy o

Current Task n Rate n MBSource Target Action State c MB/s %e Left------------------- ------------------- ------- ----- -- ----- --- -----/dev/rdsk/c3t0d44s2 /dev/rdsk/c4t0d22s2 Copy Run N 18 16 9055/dev/rdsk/c3t0d45s2 /dev/rdsk/c4t0d23s2 Copy Run N 7 10 9702/dev/rdsk/c3t0d46s2 /dev/rdsk/c4t0d24s2 Copy Run N 18 20 8624/dev/rdsk/c3t0d47s2 /dev/rdsk/c4t0d25s2 Copy Run N 15 15 9163/dev/rdsk/c3t0d48s2 /dev/rdsk/c4t0d26s2 Copy Run N 10 15 9163/dev/rdsk/c3t0d49s2 /dev/rdsk/c4t0d27s2 Copy Run N 14 10 9702/dev/rdsk/c3t0d50s2 /dev/rdsk/c4t0d28s2 Copy Run N 5 20 8624/dev/rdsk/c3t0d51s2 /dev/rdsk/c4t0d29s2 Copy Run N 12 16 9055*x/rdsk/src_vg/vol3 *x/rdsk/tgt_vg/vol3 Copy Run N 16 10 32328

--- --- -----Total Copy: 115 15 76680Total Compare: 0 0 0

Session Name: session1Session State: ActiveAction Plan: CopyTask States: RunningNumber of Pairs: 9Total Source Size: 122160System I/O Processing: MirroringTarget Devices State: NR


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Note: Including the -summary option will display only the cumulative summary data for the session.

Displaying performance statisticsTo query statistical performance data for device pairs in your session, use the stormigrate query command with the -miostats option. This option displays the current mirror I/O performance percent (%) ratio of device pairs in migration.

If the target device is operating at a slower pace than the source device, then a percentage is displayed in the MIO Performance Ratio column. For example, the target device shown in the first device pair is operating 9 percent slower than the source device.

stormigrate query -session ombig -miostat

Current Performance Ratio for Task Pairs are

Source Target MIO Perf. %----------------------- ----------------------- ---------------*x/rdsk/ora1_src_3/vol1 /dev/ora1_TGT_1/rvol1 9 /dev/ora2_src_3/rvol2 *x/rdsk/ora2_TGT_1/vol2 43 /dev/rdsk/c4t0d4 /dev/rdsk/c10t1d0 46 /dev/ora5_src_3/rvol5 *x/rdsk/ora5_TGT_1/vol5 26 *x/rdsk/ora6_src_3/vol6 /dev/ora6_TGT_1/rvol6 21 *x/rdsk/ora7_src_3/vol7 *x/rdsk/ora7_TGT_1/vol7 15 *rdsk/ora4_src_3/tpcb01 *rdsk/ora4_TGT_1/tpcb01 30 *rdsk/ora4_src_3/tpcb02 *rdsk/ora4_TGT_1/tpcb02 28 *rdsk/ora4_src_3/tpcb03 *rdsk/ora4_TGT_1/tpcb03 43 *rdsk/ora4_src_3/tpcb04 *rdsk/ora4_TGT_1/tpcb04 31 *rdsk/ora4_src_3/tpcb05 *rdsk/ora4_TGT_1/tpcb05 26 *rdsk/ora4_src_3/tpcb06 *rdsk/ora4_TGT_1/tpcb06 27 *rdsk/ora4_src_3/tpcb07 *rdsk/ora4_TGT_1/tpcb07 34 *rdsk/ora4_src_3/tpcb08 *rdsk/ora4_TGT_1/tpcb08 34

stormigrate query -session session1 -summary

Session Name: session1Session State: ActiveAction Plan: CopyTask States: RunningNumber of Pairs: 9Total Source Size: 122160System I/O Processing: MirroringTarget Devices State: NRAction Summary: MB MB MB/s %

Action Size Left Rate Done------- ------- ------ ---- ----Copy 122160 76680 99 37



*rdsk/ora4_src_3/tpcb09 *rdsk/ora4_TGT_1/tpcb09 41 *rdsk/ora4_src_3/tpcb10 *rdsk/ora4_TGT_1/tpcb10 11 *dsk/ora4_src_3/tpcb100 *dsk/ora4_TGT_1/tpcb100 0 *dsk/ora4_src_3/tpcb101 *dsk/ora4_TGT_1/tpcb101 0 *dsk/ora4_src_3/tpcb102 *dsk/ora4_TGT_1/tpcb102 -*dsk/ora4_src_3/tpcb103 *dsk/ora4_TGT_1/tpcb103 -*dsk/ora4_src_3/tpcb104 *dsk/ora4_TGT_1/tpcb104 0

If the performance ratio displays as 0, this means that the target device is operating at a pace that is faster or equal to that of the source device. If the performance ratio displays as a dash (-), this means that at the present time there is not enough I/O being generated to accurately calculate the performance percentage ratio for the device pair.


Comparing session dataThe stormigrate compare command is used to verify source and target volume synchronization. The compare command can be used to compare data between source and target volumes before or after using the copy command to migrate data. To compare source and target volumes in a session, use the following example:

stormigrate compare -session session1

Note: To view the comparison data for a given session, use the stormigrate query or show commands.

Setting environmental variablesYou can view the available environmental variables that can be set for a session by using the stormigrate -env command. Variables can be defined for the session name (-session name), filename (-file devpairfile), interval (-i) and count (-c) options to default to a user-specified value. The syntax for setting environmental variables depends on your specific command shell (for example, csh, ksh, sh). The current setting of these variables can be displayed by using the stormigrate -def command.


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Display session propertiesTo display the various properties of all defined sessions on the system, use the stormigrate props command. Displayed properties include session, task, and action information. When used with the -session name option, displays the properties of a particular session.

To display the properties of all sessions on the system, type:

stormigrate props

To display the properties of a named session, use the following example:

stormigrate props -session session1

The following example displays the output from the stormigrate props-session command.

stormigrate props -session session1session:session ID :session1session creator uid/euid: 0/0session creator gid/egid: 1/1session create time: Tue Jan 17 12:12:17 2006session action: Passthrusession tasks:

Clean up old session dataYou can delete all defined sessions from the system including any configuration files that are maintained as part of the sessions by using the stormigrate cleanup command. This command is used to initialize the state of the system to a clean state. When used with the -all option, any log files residing in the /var/EMCom/log will also be deleted.

To delete all sessions on the system, including the log files and return the system to a clean state, type:

stormigrate cleanup -all

WARNING: Cleanup will delete all defined sessions and log filesAre you sure you want to cleanup the configuration[Y/N]?YThe configuration was removed successfully

Note: It is recommended you use the cleanup command before removing the Open Migrator/LM software from the system.



Note: For selective deletion capability and to maintain certain log files, use the delete command to select individual sessions for deletion.

Postmigration proceduresOnce volumes have been successfully migrated, applications can be redirected to use the new target volumes. The only point of disruption in the migration process is re-pointing the application to use the new target volumes so that the source volumes could potentially be re-purposed.

For example, in the case of migrating under a file system application, a basic process would include the following steps:

1. Quiesce/stop the application.

2. Ensure that all buffers have been written out to disk by running the sync command (that is, sync;sync;sync).

3. Un-mount the source devices.

4. Deactivate the Open Migrator/LM session (that is, stormigrate deactivate -session name).

5. Change the device special file section designating mount specification (that is, /etc/fstab) from the source volume to the target volume.

6. Mount the target devices.

If satisfied with the integrity of the file system and data on the target volume, the old source volume could now be re-purposed and the session deleted.

Note: Once data has been migrated, it is the responsibility of the user to determine the best process for re-pointing their database management application to the new devices.


78



A

This appendix describes the stormigrate command for data migration operations.

◆ Conventions ........................................................................................ 80◆ stormigrate .......................................................................................... 81

Command Reference

Command Reference 79

80

Command Reference

ConventionsThe categories of information shown below (similar to UNIX man pages) are listed for the stormigrate command, where applicable.

◆ Command name appears in bold typeface at the top of a page followed by a brief description of what the function does.

◆ SYNTAX lists the arguments and options for each command.

◆ DESCRIPTION provides a description of the command.

◆ ARGUMENTS explains the command arguments.

◆ OPTIONS explains the command options.

◆ PARAMETERS explains the command parameters.

◆ RETURN STATUS specifies the primary success and failure codes for each command.

◆ EXAMPLES provides examples of the syntax for various commands.


Command Reference

stormigrateThe EMC Open Migrator/LM command (stormigrate) for UNIX performs data migration and comparison control operations from a host to copy data from a source volume to a target volume.

SYNTAX

stormigrate [-def][-env][-help]

stormigrate -session name

create [-file devpairfile] [-skip_label_sector][-noskip_label_sector]

delete [-force]add sourcedev targetdev [-skip_label_sector]

[-noskip_label_sector]activatedeactivatepauseresumerestartverify [-i Interval] [-c Count] [-v]query [-i Interval] [-c Count] [-summary] [-v]

[-blocks | -kbytes | -mbytes | -gbytes][-miostat]

show [-summary] [-v] [-blocks | -kbytes | -mbytes | -gbytes]

copy [-force]compare [-force]props

stormigratetune [-iosize kilobytes] [-ceiling megabytespersec]

[-checkpointsize megabytes] [-nthreads number of mover threads] [-mio_perf_ratio percentage] [-mio_recover_action action]

listcleanup [-all]

DESCRIPTION The stormigrate command performs data migration control operations on pairs of volumes (source/target) added to a session or defined in a device file. Operating from a production host, Open Migrator/LM software is implemented as a host-based kernel driver that can copy data at the block level for volumes mounted (active) to the host. During migration, the source volume can remain operational for I/O to its source and the target volume is set as not ready to the production host. Additionally, the target volume should

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Command Reference

be set as not ready or read/write disabled to any other attached hosts that can access the volume.

The stormigrate command provides mirroring and background copy functions that can be used to synchronize data images on one or more source and target volumes, LUNs or LUN partitions. Open Migrator/LM operates in sessions to manage multiple image pairs uniformly as a group.

ARGUMENTS activate

Activates a defined session and establishes the session in the kernel driver. To activate a session, one or more volume pairs (source/target) must have been previously added or volume pairs must have been provided in a device file (-file) at the time the session was created.

add

Associates a source volume (source dev) and target volume (target dev) with a created session.

cleanup

Deletes all defined sessions on the system including any configuration files that are maintained as part of the sessions. Used with the -all option to additionally clean up any log files associated with the sessions. Command is used to initialize the state of the system to a clean state.

compare

Compares source and target volume data in the session. The session must have been previously activated to begin comparing.

copy

Begins the copying process for volume pairs (source to target) in the session. The session must have been previously activated to begin copying.

create

Defines a new session and assigns a session name (-session name).


Command Reference

deactivate

Deactivates an activated session. Effectively ends the kernel driver for the specified session. When deactivated, the session will be in an inactive session state.

delete

Deletes a session. The -force option must be used if the session is active. Persistent configuration and status records of the session are deleted.

CAUTION!Forcing the deletion of a session could result in an incomplete volume copy or compare if the operation is in process.

list

Lists all currently defined sessions. Displays session names and status information for each.

pause

Pauses a session and temporarily stops the copying or comparing of volumes. Suspends the kernel driver tasks at their current data volume offsets.

props

Displays the various properties for all defined sessions on the system, including session, task, and action information. When used with the -session name option, displays the properties of a particular session.

query

Queries the status of a given session. Reports state and status information for each volume pair, followed by a summary for the entire session. Information can be displayed in various units by specifying the following options: -blocks, -mbytes, -gbytes, or -kbytes.

restart

Restarts any failed tasks having an error or MIOT status in a session.

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resume

Resumes a paused session and continues the operation from where the tasks suspended.

show

Displays current configuration data for each volume pair in a given session, followed by a summary for the entire session. Information can be displayed in various units by specifying the following options: -blocks, -mbytes, -gbytes, or -kbytes.

tune

Tunes session performance at the kernel level. Allows the modification of certain parameters. Can be used to preserve system bandwidth for data migration during peak hours of operation. To view the tune parameters currently in effect, specify the tune command without options. Used with the following options: -iosize, -ceiling, -checkpointsize and -nthreads.

verify

Verifies the existing state of a given session. Used to poll the completion status of an activated kernel driver session.

OPTIONS -all

Used with the cleanup command to clean up the log files associated with the sessions.

-bl[ocks]

Displays volume unit output in operating system blocks.

-c[ount]

Specifies the number (count) of times to display.

-ceiling

Sets the maximum bandwidth (in megabytes per second) for the target device to be used when copying data. The software throttles all data transfer operations so that the aggregate bandwidth remains at or below the specified ceiling value. Value can be between 1 and 10,000 megabytes. The default value is 1


Command Reference

megabyte. When used with the max qualifier, applies the maximum amount of bandwidth available for your system to all sessions.

Note: Setting the ceiling parameter to max may impact the performance of other programs running on the system.

-checkpointsize

Sets the size of the interval (in megabytes) between updates to the data mover’s property records. This parameter can be updated at any time and will have an immediate effect. Value range can be set from 32 to MAXINT. The default value is 256. Setting the value to NONE indicates that the data movers will only update the properties records for a final status update.

-def

Displays the values of any environmental variables that have been set for a specified session name, file, interval or count. Optional environmental variables must be specified as follows:

STORMIGRATE_SESSIONSTORMIGRATE_FILESTORMIGRATE_INTERVALSTORMIGRATE_COUNT

-env

Used to display available environmental variables that can be set.

-force

Used with the delete command to force the deletion of an activated session.

When a session is paused using the pause command, can be used with the copy or compare command to force the session to start the intended action from the beginning of the session.

-gb[ytes]

Displays volume unit output in gigabytes.

-help

Provides brief, online help (-h) information.

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-i[nterval]

Specifies the interval of time (in seconds) to repeat the command. The command will sleep for the specified number of seconds between reports.

Note: If the (-c) option is not specified and an interval (-i) is specified, the program loops continuously to produce infinite displays.

-iosize

Used with the stormigrate tune command to set the input/output buffer size (in kilobytes) to be used for data transfers. Values can range from 64 K to 128 K. The default value is 64 K.

-kb[ytes]

Displays volume unit output in kilobytes.

-mb[ytes]

Displays volume unit output in megabytes.

-mio_perf_ratio

Used with the stormigrate tune command to set the write performance ratio between mirrored pairs. The write performance ratio is the maximum allowable difference for operations between device pairs. Values can range from 110 percent to 500 percent. The default value of 200 percent allows Open Migrator to copy and mirror to target devices operating at one half the speed of the source device before triggering a recovery action.

-mio_recover_action

Used with the stormigrate tune command to set a recovery action in the event that the performance ratio threshold (-mio-perf_ratio) between device pairs has been exceeded. Values are either: ignore, log, or terminate. If set to ignore, no action is taken. If set to log, a warning message is written to the system log file. If set to terminate and Open Migrator is actively copying or comparing, the action is suspended but mirroring continues. If set to terminate and Open Migrator is only


Command Reference

mirroring, the mirroring will be disabled. The default setting is terminate. The session may be restarted again using the restart command after all other task have finished.

Note: Refer to “Setting a recovery action for mirrored pairs” on page 69 for additional information.

-miostat

Used with the stormigrate query command to display the current write performance ratio of device pairs in migration.

-noskip_label_sector

Used to migrate the sector (VTOC block) that contains the label on a Solaris device during migration. Used with the create or add arguments.

-nthreads

Used to set the size of the kernel module’s number of available threads that are used to process data mover tasks. This parameter can be updated at any time and will have an immediate effect. Value can be set between 1 and 64. The default value is 16.

-se[ssion]

Identifies the session name. The session name can be any alphabetical or numeric character and cannot exceed 32 characters in length.

-skip_label_sector

Skips the sector (VTOC block) that contains the label on a Solaris device during migration. Used with the create or add arguments.

-summ[ary]

Used to display only the summary information for a given session.

-v

Used with the query, show and verify commands to display the full volume pathname.

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PARAMETERS devpairfile

The name of the text file that contains the source and target volume pairs for the session. The device pair file must specify one volume pair (source dev and target dev) per line, separated by spaces. Lines beginning with a pound sign are ignored.

name

The name assigned to the session.

sourcedev

The physical or raw device name of the source volume.

targetdev

The physical or raw device name of the target volume.

RETURN STATUS The following are possible statuses that can be returned by this command (for example, in a UNIX C shell, returned using echo $status):

Code Description

0 STORMIGRATE_RC_SUCCESSIndicates that the session operation was successful.

1 STORMIGRATE_RC_SESSION_DOES_NOT_EXISTIndicates that the specified session does not exist.

2 STORMIRATE_RC_SESSION_ACTIVATEDIndicates that the session is currently activated.

3 STORMIGRATE_RC_SESSION_DEACTIVATEDIndicates that the session is not currently activated.

4 STORMIGRATE_RC_SESSION_ERRORIndicates that the session encountered an error during session operation.

5 STORMIGRATE_RC_SESSION_NOT_COMPLETEIndicates that the session operation has not completed.

STORMIGRATE_RC_<status_code>Indicates that the session operation has failed. Identifies other status codes that specify why a function could fail.


Command Reference

EXAMPLES The following brief example shows an Open Migrator/LM session for volume pairs defined in a device file (devfile1). Additional volume pairs are added to the session. The session (copyses1) is paused and is then resumed to continue data migration. The session is then queried, verified for completion and compared before being deleted.

stormigrate create -session copyses1 -file devfile1 -noskip_label_sectorstormigrate add -session copyses1 /dev/rdsk/c1t6d0s6 /dev/rdsk/c2t6d0s6 -noskip_label_sectorstormigrate activate -session copyses1stormigrate props -session copyses1stormigrate copy -session copyses1stormigrate pause -session copyses1stormigrate resume -session copyses1stormigrate query -session copyses1 -i 10 -c 3stormigrate compare -session copyses1stormigrate verify -session copyses1 -i 15 -c 3stormigrate deactivate -session copyses1stormigrate delete -session copyses1stormigrate cleanup -all

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B

This appendix provides examples using the stormigrate command for data migration operations.

◆ Migrating Oracle databases.............................................................. 92

Examples

Examples 91

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Examples

Migrating Oracle databasesThe following CLI examples show how you can use Open Migrator/LM to migrate an Oracle database from an EMC Symmetrix® storage array to an EMC CLARiiON storage array. The database is Oracle 8i running on a Hewlett Packard (HP) PA-RISC system. The operating system is HP-UX 11iv1 (version 11.11).

In this scenario, the application using the Oracle database is a mission critical application, which can have very limited, planned outages. Unplanned outages of the application or any activities that impact the application’s performance cannot be tolerated.

The environment setup hosting the Oracle database uses an EMC Symmetrix array to provide storage for the database engine. Furthermore, instead of the native logical volume manager available on HP-UX systems, VERITAS Storage Foundation for Databases is used as the platform for managing the storage on the server.

Due to an application redesign, the Oracle database environment is now less critical and can be migrated from one storage array to another for consolidation purposes. In addition to migrating the Oracle database, the administrator would like to eliminate the use of VERITAS Storage Foundation for Databases. Although the criticality of the database has been reduced, it still plays an important role in the day to day business activities. Hence, the administrator would like to have minimal performance impact and small planned outages during the migration.

Identifying devices to migrate

Data migrations are performed for a number of reasons. These include, but are not limited to, server consolidation, storage technology upgrades, performance tuning and application balancing to optimize IT storage resources. When applications are migrated to optimize storage utilization, it is critical to identify all devices that are associated with the application. Failure to do so can result in unplanned application outages and data corruption when the original storage resources are redeployed.

The requirements discussed in the above section clearly define the reason for the migration of the Oracle database and optimization of IT resources. Therefore, as a first step to the migration, it is critical to properly identify all host devices associated with the application.


Examples

This can be achieved in a number of ways:

◆ The database administrator normally maintains a list of all devices that are allocated to databases. If you do not have the information available, simple SQL queries to the database can be used to obtain the information.

◆ Storage administrators managing the environment can use tools at their disposal to determine the storage devices that have been allocated to the hosts.

◆ Storage resource management tools such as EMC ControlCenter® and EMC StorageScope™ can provide reports that detail the storage allocation to various databases and applications.

◆ The Storage Resource Management (SRM) component of EMC Solutions Enabler can be utilized to determine both the host and storage devices associated with a number of applications and databases.

In this example, the EMC Solutions Enabler command line interface (CLI) is utilized to determine which devices need to be migrated from the Symmetrix array to the CLARiiON array. Figure 4 shows all schemas that are associated with the Oracle database to be migrated. It can be seen from the figure that two environmental variables, SYMCLI_RDB_NAME and SYMCLI_RDB_CONNECT, are necessary for EMC Solutions Enabler to provide the information. A database object SRM CLI command (symrdb) is used to list the schema of the Oracle database.

Figure 4 Using Solutions Enabler to determine the schema of Oracle database

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Examples

Once the schemas associated with the Oracle database have been identified, all files constituting the database need to be determined. The SRM component of EMC Solutions Enabler can provide that information. Figure 5 shows a partial listing of the Oracle database files associated with the database to be migrated. It is important to note that the filename returned by the command could be a symbolic link pointing to a file in a different file system. Further examination of the database structure is essential to determine the logical volumes associated with the database files.

The symrdb command can also provide detailed information about the data file associated with supported applications. The output from execution of this command on one of the database files is shown in Figure 6 on page 95.

Figure 5 Determining database files to be migrated


Examples

It can be seen from Figure 6 that the file under scrutiny is an object on a VERITAS file system.

Figure 6 Detail showing the location of database file

The output from the symrdb show FILE command also provides information about the physical devices, volume groups (in case of VERITAS volume manager, disk groups) and the logical volume hosting the database file. Refer to Figure 7 on page 96.


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Examples

The logical volume identified in Figure 7 will be provided at a later time to Open Migrator/LM as one of the devices for migration.

Figure 7 Determining disk groups associated with Oracle database

All of the devices associated with the Oracle database can be identified using the process described above. EMC Solutions Enabler also offers an option for collapsing the process of identifying database files, and obtaining its details into a single step.

The symrdb command line shown on page 97 leverages this option to identify the logical volumes and file systems associated with the SYS schema. Repeating the process for every schema that needs to be migrated will provide a complete listing of the logical volumes that need to be migrated. The logical volumes associated with the schema TPCB are shown in Figure 9 on page 97.


Examples

Figure 8 Identify logical volumes and file system with schema SYS

Figure 9 Identify logical volumes and file system with schema TPCB


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Creating volume groups and logical volumes on target devicesThe architectural details of the logical volumes identified in the previous section need to be determined in order to create the appropriate structures on the target devices. The method to do this is presented using one of the logical volumes constituting the schema TPCB. Figure 10 shows how to obtain the configuration details of logical volume tpcb01 using the vxprint command. It can be seen from the figure that the logical volume is 2200 MB in size and is spread across six sub-disks (oracle004-01 through oracle009-01). Once the configuration details of all of the logical volumes to be migrated has been determined, the appropriate devices can be configured on the CLARiiON storage array and presented to the host.

Figure 10 Configuration details of logical volume tpcb01 in schema TPCB

Figure 11 on page 99 shows how the vgdisplay command is used to present the details of one of the target volume groups (/dev/ora_TGT_1), which will be used for the migration. It is important to note that the target volume group is created using the native logical volume manager (HP-UX LVM) and not the VERITAS volume manager.

The appropriate target logical volumes can be created by obtaining information from the source logical volumes. The configuration of the target logical volume does not need to match that of the source logical volume. Although, changes may be needed due to the performance characteristics of the target devices or to address architectural flaws present in the original configuration.


Examples

Figure 11 Creating target volume groups using EMC CLARiiON devices

Figure 12 on page 100 displays details of target logical volume that will be used to migrate the VERITAS volume discussed earlier (tpcb01).


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Examples

Figure 12 clearly shows the differences between the source and target logical volumes. The target logical volume is not only larger than the source logical volume, but also has a different stripe size. Once all the target logical volumes have been configured, Open Migrator/LM can be configured to initiate the migration.

Figure 12 Comparing source and target logical volume pairs


Examples

Setting up EMC Open Migrator/LMEMC Open Migrator/LM software contains two components, a kernel driver and a management interface. The kernel driver is responsible for the copying of the data from the source devices to the target devices. The management interface is used to instruct the kernel driver about the pairing of devices. The management of migration is performed using a construct known as a "session." A session is a logical grouping of device pairs that enables migrations to be performed in a consistent fashion. For example, a session could include all logical volumes used by an application or database.

The source and logical volumes identified in the previous section are listed in a device file. The device file will be used as the input to the management interface of EMC Open Migrator/LM. The logical volumes that need to be migrated are listed individually on a separate line. The contents of the file that will be used for the Oracle database migration is shown in Figure 13.

Figure 13 Device file listing the source and target logical volumes


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Examples

Open Migrator/LM performs migrations by copying data at a block level. However, as shown in Figure 13 on page 101, character devices are listed in the device file to be used as input to Open Migrator/LM.

Note: Refer to “Creating a device file” on page 54 for more information.

The management interface for Open Migrator/LM is accessed via the stormigrate CLI command. The command uses four optional environmental variables (if set)- EMCOM_SESSION, EMCOM_FILE, EMCOM_INTERVAL and EMCOM_COUNT. These variables provide a convenient mechanism used to reduce the risk of typographical errors when executing commands that control and manipulate Open Migrator/LM.

The set value for any of the environmental variables can be overridden by providing new values when executing the stormigrate command. The environmental variables that are set for the migration discussed in this example and are shown in Figure 14.

Figure 14 Setting environmental variables


Examples

Creating the SessionFigure 15 shows how the migration session (session name VxVM2LVM) is created using the stormigrate create command. The session is created using the device file shown in Figure 13 on page 101 as input. Because a session name and a filename are not identified in the command line, the session is created using the definitions that were set in the environmental variables (refer to Figure 14 on page 102). The stormigrate show command is then used to list the current session information.

When the session is created, the structures necessary for managing the session are created. The kernel driver component of Open Migrator/LM is not yet involved at this point.

Figure 15 Creating the Open Migrator/LM session

Figure 16 on page 104 shows which I/O’s are being actively processed by the physical devices associated with the source logical volumes but not the target logical volume.


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Examples

Figure 16 I/O activity on source logical volumes

Activating the sessionWhen the session is activated using the stormigrate activate command, the kernel driver inserts itself into the I/O path. However, it is in a pass-through mode in which the I/Os to the devices are not manipulated by the kernel driver.

EMC Open Migrator/LM can be left in this state until an appropriate time to start the copy process is reached. The stormigrate copy command then instructs the Open Migrator/LM kernel driver to start the copy. Refer to Figure 17 on page 105.


Examples

Figure 17 Activating and starting the copy process for the session

Managing the sessionThe Open Migrator/LM kernel driver actively reads data from the source device and copies it to the target devices for all sessions executing the stormigrate copy command. Furthermore, any new writes generated by the applications to the source devices will be mirrored to both the source and target devices. These activities, as shown in Figure 18 on page 106, results in increased CPU, memory and I/O workload. The increased workload can severely impact the performance characteristics of the Oracle database being migrated.


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Examples

Figure 18 Increased IO activity due to copy in process

The tuning of the performance characteristics of Open Migrator/LM is managed using the stormigrate tune command. Open Migrator/LM provides six different mechanisms (options) to minimize the impact of the copy activities. Some of these mechanisms will need to be leveraged to satisfy the migration requirements described on page 92.

Open Migrator/LM allows users to determine the maximum rate at which the copy from the source to target device can take place. This is implemented using the -ceiling option. The ceiling value, by default, is set to 1 MB per second. This parameter needs to be slowly ramped to a value that will not cause any performance impact in the system environment. Furthermore, during the periods of extremely heavy workload, the copy process can be completely stopped by using the stormigrate pause command.


Examples

Note: Parameter changes made using the -ceiling option take effect immediately for all running sessions.

Refer to “Setting the target bandwidth” on page 66 for more information.

The stormigrate tune command when used with the -iosize option allows users to set the I/O transfer buffer rate. Refer to Figure 19.

Note: Parameter changes made using the -iosize option affect only new sessions that have not yet been activated in the kernel.

Figure 19 Tuning IO size for the session

Refer to “Tuning session performance” on page 66 for information on all of the available tuning parameters.


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The copy session can be paused and resumed at any point by executing the stormigrate pause and stormigrate resume commands.

Figure 20 shows a pause and resume of the copy process for the session (VxVM2LVM).

Figure 20 Pausing and resuming the session

Completing the migrationThe status of the copy process can be verified by executing the stormigrate command with either the query or verify option. The query option provides detailed information about the progress of each device pair for the interrogated session. The verify command, on the other hand, returns a non-zero value if any of the device pairs is still being copied, which makes this option appropriate for use in command line scripts.


Examples

EMC Open Migrator/LM also supports a compare operation (instead of a copy operation). When the kernel driver is sent the stormigrate compare command, it performs a block by block comparison of the source and target devices. The compare operation can be used before or after a copy operation. To test the progress of the compare operation, you can use the stormigrate query or verify options.

Once the copy or compare process from the source devices to the target devices has completed, Open Migrator/LM will continue to maintain the synchronicity between the source and target devices. This enables the actual cutover to the target devices to be scheduled and performed at a convenient time. For the example migration being discussed, this will need to be carried out during a planned maintenance window.

The Oracle database needs to be shutdown before the migration from the source devices to the target devices can be completed. If the application provides tools to test the validity and integrity of the data, they should be run just before the process to switch over the applications is started. The Oracle database discussed in this document, as shown in Figure 21, does provide a mechanism to verify the integrity of the data. After the completion of the migration, the same procedure needs to be executed to ensure that the migration was successful.

Figure 21 Verify and stop Oracle database before completing the migration


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The Open Migrator/LM session needs to be deactivated after the Oracle database has been successfully stopped and the file systems associated with the database have been un-mounted. The target device can be then mounted to either the same location as the original source devices or to new location. The symbolic links associated with the Oracle database will need to be updated if the target devices are mounted at a new location. These steps are shown in Figure 22.

Figure 22 Unmount source devices and deactivate the session

The Oracle database, as displayed in Figure 23 on page 111, can now be started on the target devices. However, before end-users access the database, the integrity of the data should be checked using the tools provided by the application (if any).


Examples

Figure 23 Starting Oracle on target devices


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Figure 24 displays the results from the verification tests conducted on the database. A quick comparison of the results displayed in Figure 24 with those in Figure 21 on page 109, clearly show that the migration was completed successfully.

Figure 24 Testing the integrity of the Oracle database on target devices

ConclusionThe use case discussed throughout these examples clearly show the powerful capabilities of EMC Open Migrator/LM for migrating Oracle databases. It is important to note that the procedure described in this example can be used for migrating other applications and databases on various supported operating systems. Furthermore, the procedure can be modified to accommodate other volume managers, and also different source and target storage arrays.


Index

Cconcurrent migrations 20creating a session 57

Ddata synchronization 20device file 54

Ffile system 25

II/O stack layers 23I/O subsystem 23

LLinux host install

Red Hat Enterprise Linux AS 46log file 21

Mmigration

mount point 20planning 23to a different volume size 20to a different volume type 20with a file system 25with a volume manager 24

migrationsconcurrent 20

mount point migration 20

Ppost-migration 27, 77provisioning target volumes 24

Rredirecting applications 77

Sstopping daemon processes 45stormigrate 27, 81stormigrate commands

activate 62add 60cleanup 76compare 75copy 63create 57deactivate 62delete 65list 61pause 63props 76query 73, 74restart 65resume 64show 61tune 66verify 72

UUNIX host install

HP-UX 31


114

Index

IBM AIX 36Sun Solaris 41

Vvolume manager 24


Documents

Open Migrator/LM for UNIX and Linux CLI · EMC Corporation Corporate Headquarters: Hopkinton, MA 01748-9103 1-508-435-1000 EMC Open Migrator/LM for UNIX and Linux CLI Version 3.10