vnxe VP Operations

Copyright © 2012 EMC Corporation. All rights reserved

Upon completion of this module, you should be able to:

•Implement Virtual Provisioning

• Create Thin and Data Devices

• Create Thin Pools

• Add Data Devices to Thin Pools

• Bind Thin Devices to Thin Pools

1 Module 3: Virtual Provisioning Operations


Upon completion of this lesson, you should be able to:

•Implement Virtual Provisioning with SMC





Module 3: Virtual Provisioning Operations 2


Like all aspects of storage configuration, the first step is planning. However, with Thin Devices less planning is required. User’s don’t have to think about back-end layout and there is minimal efficiency impact of over-estimating the required capacity.

Later in this module, a review of configuring Thin Devices, Data Devices, and Thin Pools using SMC and Solutions Enabler is shown. Once the Thin Devices are configured, they can be mapped, masked, and used like any other device.

Symmetrix VMAXe arrays are pre-configured with Thin Pools and Data Devices, so steps 2-4 would not need to be performed. Instead one would simply create Thin Devices and then bind them to the appropriate Thin Pool and then mask the same to a host for use. However for the sake of completeness we will cover the creation of Data Devices and Thin pools in this module.



Let us take a look at creating Symmetrix Devices using SMC. Right-click on a Symmetrix, choose Device Configuration and then Create Device to launch the dialog Device Configuration - Create Device dialog. On the Symmetrix VMAXe array the Create Device dialog is used to create Gatekeeper, Thin, Data, and Save devices. Thin and Data devices are used for Virtual Provisioning. On a VMAXe array the Save devices are used by SRDF/A Delta Set Extension.



To create Thin Devices in SMC, Right-click on a Symmetrix, choose Device Configuration and then Create Device to launch the Create Device dialog.

Click the Thin Device tab in the Create Device dialog and enter the number of devices, the Configuration (TDEV in this example), the Emulation (FBA, CELERRA_FBA, etc.), Device capacity in cylinders – The drop down list will show you the existing devices sizes on the Symmetrix.

The device creation dialog also has an option to bind the new Thin Devices to a Thin Pool and to specify the pre-allocated capacity. In this example we will bind the devices to the SATA_R6 pool.

Please note that if the VMAXe array were setup for SRDFe one would have the option of creating RDF1+TDEV or RDF2+TDEV devices as well. When create RDF devices the Device Configuration interface will require adding additional configuration information as it relates to the creation of RDF devices.

Click Add to Config Session List to add this configuration request to the Config Session view.

The Gatekeeper tab is used to create Gatekeeper devices.



Symmetrix VMAXe arrays are pre-configured with Data Devices. So typically one would not have to create new Data Devices.

To create Data Devices in SMC, Right-click on a Symmetrix, choose Device Configuration and then Create Device to launch the Create Device dialog.

Click the Data Device tab in the Device Configuration – Create Device dialog and enter the number of devices, the Configuration (2-Way Mir, RAID-5 or RAID-6), the Emulation (FBA only), Device capacity in cylinders – The drop down list will show you the existing devices sizes on the Symmetrix.

Be sure to specify the Disk Group in which the new Data Devices will be created. If you do not specify a disk group the Data Devices will be spread out over the available disk groups.

The device creation dialog also has an option to add the new Data Devices to a Thin Pool. The device can also be Enabled (Disabled is the default) when added to the Thin Pool. After the Data Device is added to the pool the pool can be automatically rebalanced.

Click on Add to Config Session List to add this configuration request to the Config Session view.

If the VMAXe array were setup for SRDFe one would also see the Save Device tab. The Save Device tab is used to create Save devices for use by SRDF/A DSE.



All Configuration tasks in SMC have to be committed by clicking the Commit All button in the Config Session view.

In this example, 4 thin devices and 4 RAID 6 (6+2) data devices are being created.

The bottom part of the slide are excerpts of the Config Session log. In this example, we can see that the creation of these devices took about two minutes.



Symmetrix VMAXe arrays are pre-configured with Thin Pools. So typically one would not have to create new Thin Pools.

On a VMAXe array SMC can be used to create Thin Pools and SRDF/A DSE Pools. Right click on a Symmetrix (or the Pools folder under a Symmetrix) and choose Device Pool Management > Create Device Pool. This will launch the Device Pool Management – Create Device Pool dialog shown on the slide.

To create a Thin Pool, set the pool type to Thin and enter a name. For Thin Pools, the maximum subscription limit can set.

Optionally, one can add Thin Devices to the pool and enable them. To add devices to the pool, pick the devices from the Available column and click the Add button to move them the Target column. The Available column will show Data Devices for Thin Pools. Only disabled Data Devices will be shown.

The Rebalancing Variance and Maximum Rebalancing Scan Device Range can also be set. We discussed these features in Module 2. We will discuss the Pool Reserve Capacity setting in the FAST VP Modules.



One can create a Thin Pool via SMC with the technique shown on the previous slide. Alternately one can use the Create Thin Pool Wizard which can be launched from the Dashboard or the Tasks Page. The Wizard will create the Thin Pool and populate the same with Data Devices. The wizard will try to use existing data devices which meet the criteria. If devices do that meet the criteria are not available then the wizard will create the required data devices and then populate the thin pool.



To Bind/Unbind Thin Devices to a device pool in SMC, right click on the Thin Pool and choose Device Pool Management > Bind/Unbind Thin Devices.

All unbound Thin Devices will be listed in the Available column.

To bind a device, highlight it in the Available column and click the Add button to add it to the Target column. The pre-allocated capacity for the device can also be specified (in Cylinders,

MB or GB). Pre-allocation reserves pool storage before it is needed, it can be during the bind step or afterwards. Pre-allocation can be persistent.

To unbind a device, highlight it in the Target column and click the Remove button. Like all the other configuration tasks, click the Add to Config Session List button and then go to the Config Session view to commit the task.



Upon completion of this lesson, you should be able to:

•Implement Virtual Provisioning with SMC





Module 3: Virtual Provisioning Operations 11


The output on this page is intended to show the Symmetrix VMAXe environment where the VP operations are going to be performed. Symmetrix 000195900495 is used in the examples.

The command displays the size of the existing Symmetrix thin devices in the cylinders.

Later in the module, when Thin Devices are created, they will be the same size as these, which in this case is 1100.



The syntax related to creating Thin Devices is available in Chapter 1 of the Array Controls Manual.

It is usually a good idea to use the prepare option in Config Manager to make sure that the syntax for the command file is in order. Once the prepare is successful, the commit action makes the necessary changes in the Symmetrix.



After configuring Thin Devices, they can be viewed using the symdev list command.

Note: that TDEVs are not ready to a host until bound to a Thin Pool.

Note: that DA:IT show NA in that no back-end resources are allocated to Thin Devices.



Before creating Data Devices we will take a look at a summary of the Disk Groups in this Symmetrix Array.

We see that this array has SATA, 10K FC, 15K FC and EFD disks in four different disk groups.

We will create some data devices on the 15K FC Disk Group.



While the example here is for lab demonstration purposes, please remember the recommendations for configuring Data Devices in production environments.

Data Devices in a pool should be the same size. They should be created on drives the same size and speed. They should be spread widely across the back-end and should be as large as practically possible. Please note that in this example we are showing the syntax for creating RAID1 protected Data Devices. Data devices can also have RAID5 or RAID6 protection. In this example the Data Devices will be created on Disk Group 3. Which is the 15K FC Disk Group as seen on the previous slide.



After configuring Thin Devices, they can be viewed using the symdev list command.

Data Devices are private devices and are not directly visible to a host. Data Devices are identified by the device type of DT. You can use the -nonpooled option to limit the list to Data Devices that have not been added to a pool.



There is no default Thin Pool. Therefore, at least one user defined Thin Pool must be created before Virtual Provisioning can be used.

All Data Devices in a Thin Pool must have the same emulation and protection type.



Add Data Devices to the pool and enable them.



The pool P1 that we had created is listed along with the other thin pools that were already on the Symmetrix.

Pool P1 is identified as an enabled Thin Pool. The pool is enabled as soon as it contains one enabled Data Device.

The track numbers reflect the size of two Data Devices, each 1100 cylinders in size. Since each cylinder comprises of 15 tracks, the actual number is 1100*2*15 = 33000 tracks. At the moment none of the tracks in Pool P1 are used. There are no thin devices bound to P1.

The Pool Type is T indicating that this is a Thin Pool. The Tech is F indicating that this is a FC pool.



There are two options that can be used with the show command to display more information about the pool. The –all option shows information on enabled and disabled Data Devices, while the –detail option includes a listing of the Thin Devices.



If Thin Devices were to be bound to a pool at the time of creation, the syntax would read as follows:

create dev count=4, size=1100,

emulation=FBA, config=TDEV,

binding to pool P1;



In the prior page we bound 4 TDEVs to the pool WB. As a result, one extent, or 12 tracks were allocated to each TDEV. Also the TDEVs are now ready and available for Read Write operations once they are mapped and masked to a host.



The detailed output of the Thin Pool is shown on the slide. The Thin Pool has two enabled Data Devices.

This slide shows the top part of the output, the rest of the output is shown on the next slide.



The bottom part of the detailed output shows the correct percentage subscription of the Thin Devices compared to the pool. Each Thin Device capacity is 16500 tracks, which means that each TDEV, if filled to capacity would use up 50% of the available TDAT space.

4 Thin Devices filled to capacity would require 200% of the pool space as indicated in the “Subs %” column.



As shown in the syntax for the “bind” command below, pre-allocation can be done at the time of binding the Thin Devices to the pool. It is used to reserve storage space in a pool before the space is actually required. This can be useful when we know in advance that the device in question will require a certain amount of space.

create dev count=4, size=1100,

emulation=FBA, config=TDEV,

binding to pool P1, preallocate size=1100;

To use the persistent allocation method, add the allocate_type=persistent option to the syntax.



The command output shows that additional space has been pre-allocated for the first two TDEVs in the pool. Nothing has been written to the TDEVs yet.



The detailed listing of the pool information confirms the existence of the pre-allocated space for the Data Devices.

This slide shows the top part of the output, the rest of the output is shown on the next slide.



The bottom part of the detailed listing of the pool information confirms the existence of the pre-allocated space for the Thin Devices.



The process of mapping and masking the Thin Devices has not been shown here. We will cover autoprovisioning in the module 5.

The procedure to map and mask Thin Devices in a VMAX array, is identical to that of regular devices. After mapping and masking, a reboot (or bus scan) has to be performed in order to make the devices host visible. Remember to run symcfg discover after the reboot so the new pdevs are recognized by SYMCLI.

In the Solaris environment, format followed by newfs commands allow a file system to be created on the Thin Device. The Thin Device is now ready for use.



As a result of creating a file system on one of the Thin Devices (TDEVs) on Solaris, an additional (2488 – 1620) 868 tracks were allocated while 561 tracks (roughly 35 MB) were written. The Symmetrix array uses a round-robin mechanism to balance the allocation of extents across all the data devices in the pool that are enabled and that have remaining unused capacity. In this example we only have two data devices and we that the number of allocated tracks for each of the data devices is similar.



Key points covered in this module:

•Virtual Provisioning implementation with SMC and SYMCLI

• Creation of Thin and Data Devices

• Creation of Thin Pools

• Addition of Data Devices to Thin Pools

• Binding Thin Devices to Thin Pools



1. See slide 14

2. See slide 6, 8, 19

3. See slide 23

4. See slide 5, 10, 26

5. See slide 9


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vnxe VP Operations