V-VOLs with data direct mapping enabled

Provisioning Guide for VSP One Block

Version
10.2.x
Audience
anonymous
Part Number
MK-23VSP1B012-00

By using a V-VOL for which data direct mapping is enabled, you can create a mapping of an external volume larger than 4 TB without having to change its capacity as a V-VOL of the local storage system.

A V-VOL with data direct mapping enabled is associated with these pool-VOLs: an external volume for which the data direct mapping attribute is enabled and a pool-VOL with System Area. If you want to create a pool with data direct mapping enabled, define at least one volume to use as the pool-VOL with system area in a pool. For more information about the requirements for the volume used as the pool-VOL with system area, see Prerequisites for creating pools.

By using CCI, you can create an external volume group with data direct mapping enabled and change the pool attribute to the data direct mapping attribute. These operations are not available by using VSP One Block Administrator, VSP One Block Administrator API, or REST API.

To use V-VOLs with data direct mapping enabled, you must enable data direct mapping for pool-VOLs, pools, and V-VOLs.

The following figure shows data direct mapping enabled on the external volume and on the V-VOL.


V-VOLs with direct data mapping

This table shows what kind of external volumes can be added as pool-VOLs.

Operation Data direct mapping attribute of external volumes
Disabled Enabled
Add volumes to a pool with the data direct mapping attribute enabled The volumes can be added. The volumes can be added.
Add volumes to Dynamic Provisioning pools The volumes can be added. The volumes cannot be added.

This table shows what kind of operations can be performed when the data direct mapping attribute of a Dynamic Provisioning pool is enabled or disabled.

Operation Data direct mapping attribute of the pool
Disabled Enabled
Add an LDEV for which the data direct mapping attribute is disabled to the pool The operation can be performed. The operation can be performed.
Add an external volume for which the data direct mapping attribute is enabled to the pool The operation cannot be performed. The operation can be performed.
Set the depletion threshold and the warning threshold The operation can be performed. The operation cannot be performed.
Set subscription The operation can be performed. The operation can be performed.
Protect V-VOLs when I/O fails to Blocked Pool VOL The operation can be performed. The operation can be performed.
Protect V-VOLs when I/O fails to Full Pool The operation can be performed. The operation can be performed.
Performing rebalancing The operation can be performed. The operation can be performed.
Define the used capacity of the pool The sum of the reserved pages capacity and the mapped capacity The sum of the reserved pages capacity and the mapped capacity
Define the licensed capacity The sum of the pool-VOLs The sum of pool-VOLs for which the data direct mapping attribute is disabled.

However, the license capacity does not include the capacity of pool-VOLs for which the data direct mapping attribute is enabled.

Expand pool The operation can be performed. The operation can be performed.

However, the capacity of pool-VOLs with System Area must be reserved in advance.

Shrink pool The operation can be performed. The operation can be performed.

However, if a pool-VOL for which the data direct mapping attribute is enabled is associated with a V-VOL, you cannot shrink the pool.

Delete pool The operation can be performed.

Note: You can delete a pool only when there are no V-VOLs associated with the pool.

The operation can be performed.

Note: You can delete a pool only when there are no V-VOLs associated with the pool.

Create V-VOL You can only create V-VOLs for which the data direct mapping attribute is disabled. You can only create V-VOLs for which the data direct mapping attribute is enabled.

This table shows what kind of operations can be performed when the data direct mapping attribute of a V-VOL is enabled or disabled.

Operation Data direct mapping attribute of the V-VOL
Disabled Enabled
Configure LU paths The operation can be performed. The operation can be performed.
Format LDEVs The operation can be performed. The operation can be performed.
Delete LDEVs The operation can be performed. The operation can be performed.
Expand V-VOLs The operation can be performed. The operation cannot be performed.
Reclaim zero pages The operation can be performed. The operation cannot be performed.
Execute the V-VOL full allocation function The operation can be performed. The operation cannot be performed.
Protect V-VOLs when I/O fails to Blocked Pool VOL The operation can be performed. The operation can be performed.
Protect V-VOLs when I/O fails to Full Pool The operation can be performed. The operation can be performed.