Nick Kieffer – XenServer Technical Lead

Disaster Recover Best Practices for XenServerSUM411

May 2013

© 2013 Citrix

Introduction

This presentation is designed to provide an introduction and overview of the integrated disaster recovery (DR) feature that allows you to recover virtual machines (VMs) from a catastrophic failure that disables your production pool, along with alternatives and best practices for a successful recovery.

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Agenda

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• Why we require recovery options• VM metadata backup and restore method• How to utilize the integrated Disaster Recovery (DR) Wizard in XenServer• Tips for a successful recovery• Resources

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Why Disaster Recovery Matters

• Every week 140,000 hard drives crash in the United States1

• In the past 2 years 50% of company’s experienced unforeseen interruptionᵒ 81% of these were closed 1 or more days2

• 43% of company’s that experience a major data loss do not reopen3

• 80% of companies that do not recover from a data loss within one month are likely to go out of business in the immediate future4

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Why Disaster Recovery Matters

• Gartner estimates only 35% of SMB have a Recovery Plan

• IDC estimates companies lose $84K per hour of downtime1

• Strategic Research estimates $90K per hour of downtime2

• Survival rate for companies without a DR plan3 <10%

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Disaster Recovery Planning

• Business Management responsible for the Business Continuity Plan (BCP)

• IT responsible for the Disaster Recovery Plan (DRP)

• Creating a successful and effective plan:1. Detection of a disaster 2. Damage Assessment 3. Recovery Time Objective4. Resume Critical Business Processes

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What is a disaster?

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Agenda

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• Why we need recovery options• VM metadata backup and restore method• How to utilize the integrated Disaster Recovery (DR) Wizard in XenServer• Tips for a successful recovery• Resources

VM Metadata backup and restore

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Manual restore using VM metadata

• First you need to reattach the SRᵒ Ensure to reattach and do not format the SRᵒ With XenServer 6 we now have SR metadata on the lun

• Brings in the VDI name and description as it was previously defined.

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Restore using the Xen text console (xsconsole)

• Select “Backup, Restore and Update” from the main menu

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Metadata restore continued…

• Select “Restore Virtual Machine Metadata”

• Choose backup date you wish to restore from (if you have multiple)

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Restore completed successfully

• For a video of this procedure, visit our Knowledge Center and search for CTX120590

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Metadata Restore using the CLI• Usage: /opt/xensource/bin/xe-restore-metadata [-h] [-v] [-y] [-n] [-p] [-x <VDI UUID>] [-u <SR UUID>] [-m all|sr]

• -h: Display this help message

• -x: Specify the VDI UUID to override probing

• -p: Just scan for a metadata VDI and print out its UUID to stdout

• -u: UUID of the SR you wish to restore from

• -n: Perform a dry run and just echo the metadata import commands (default: false)

• -l: Just list the available backup dates

• -d: Specify which date to restore from (default: latest)

• -m: Either 'sr' to restore only the VMs on the SR, or 'all' for VMs (default: all)

• -v: Verbose output

• -y: Assume non-interactive mode and yes to all questions

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xe-restore-metadata -u e1267248-3ed8-0609-11d4-c5d9760d2785 -m sr –y

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Agenda

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• Why we need recovery options• VM metadata backup and restore method• How to utilize the integrated Disaster Recovery (DR) Wizard in XenServer• Tips for a successful recovery• Resources

Integrated Disaster Recovery Wizard

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Why should I use the DR wizard?

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Now what do I do?

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• Don’t panic… You are prepared for this

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Disaster Recovery Wizard Requirements

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• SAN Replication

• Supported SR Types = FC or iSCSI

• XS Platinum license

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DR Infrastructure Requirements

• Hardware at DR site does not have to be the same• XenServer release version and patch level should be the same• Sufficient resources should be available to run the load you require on the hosts• The Disaster Recovery wizard does not control any Storage Array functionality

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What’s in the Metadata

• VM Metadata contentsᵒ Name and Descriptionᵒ Universal Unique Identifier (UUID)ᵒ Memory, Virtual CPU(s)ᵒ Networking and Storage configuration

• VM startup optionsᵒ Start orderᵒ Delay interval ᵒ HA restart priority

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Primary Site Configuration

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Disaster Recovery Wizard Primary Site configuration

• Enable database replication on the Primary Site

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Disaster Recovery Wizard Primary Site configuration

Choose SR for DR metadata location

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Disaster Recovery Wizard Primary Site configuration

• Enable database replication on the Primary Site with single command.

xe sr-database-replication uuid=<sr=uuid>

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Secondary Site Actions

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Secondary Site Actions

• Stop Array replication before performing failover processᵒ This is required for the host to gain Read/Write access to the lun(s)

• Connect to the SR on the secondary site in the event of a disaster:

xe drtask-create type=lvmoiscsi device-config:target=<target IP>

device-config:targetIQN=<target-iqn> device-config:SCSIid=<SCSI-id>

sr-whitelist=<sr-uuid>

• Find the database VDI’s on the recovery SRxe vdi-list sr-uuid=<sr-uuid> type=Metadata

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Disaster Recovery Commands

Secondary Site continued…

•Query the database VDI for VMs present:xe vm-list database:vdi-uuid=<vdi-uuid from previous step>

•Recover a VMxe vm-recover uuid=<vm-uuid> database:vdi-uuid=<vdi-uuid>

•Destroy the DR task, this will destroy any SR’s introduced by the DR task and that are not required by VMs:

xe drtask-destroy uuid=<drtask-uuid>

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Launching the Failover Wizard from XenCenter

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Locate the SR that contains the DR metadata

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Verify ‘VM configuration data exists’

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Choose VMs to failover to Secondary Site

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Choose vApps to failover to Secondary Site

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DR Wizard will restore each selected VM or vApp

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Summary of failover to ‘Secondary Site’

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VM’s recovered and running at DR site

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Agenda

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• Why we need recovery options• VM metadata backup and restore method• How to utilize the integrated Disaster Recovery (DR) Wizard in XenServer• Tips for a successful recovery• Resources

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Tips for a successful recovery

• Ensure that all the required SR’s are attached at the DR site before starting the failover

• Run monthly or quarterly “dry runs”• Have a regular backup policy in place

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Agenda

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• Why we need recovery options• VM metadata backup and restore method• How to utilize the integrated Disaster Recovery (DR) Wizard in XenServer• Tips for a successful recovery• Resources

Resources

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Resources

• XenServer 6.1 Admin Guide CTX134585• Metadata Restore process video CTX120590

• A more Open Xen = A Stronger Xen (Tom McCafferty)ᵒ http://blogs.citrix.com/2013/04/29/a-more-open-xen-a-stronger-xenserver/

• Xen Project now part of the Linux Foundationᵒ http://www.xenproject.org/

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Questions

Work better. Live better.

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Before you leave…

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