Thin Image volume requirements

Volume type

Logical volumes (LDEVs).

You cannot specify the following volumes as HTI P-VOLs:

• Pool-VOLs
• HTI S-VOLs
• Volumes belonging to a parity group with accelerated compression enabled

For more information about creating pairs using other software applications, see Sharing Thin Image volumes with other software applications.

Emulation type

OPEN-V

Path definitions

Required. The LU path definitions or a namespace on the NVM subsystem with an NVM subsystem port added for NVMe must be defined.

Not required for cascaded pairs and pairs with the clone attribute.

Volume capacity limit

256 TB

1,024 (for a P-VOL). When storing snapshot data, this number includes the number of snapshots.

Maximum number of layers for cloning: 3 (L1 to L3).

Volume type

Thin Image V-VOL (V-VOLs of provisioning type Snapshot in HDvM - SN or V-VOL for the raidcom add ldev -pool snap command in CCI) or DP-VOL.

You cannot specify the following volumes as HTI S-VOLs:

• Volumes that are already used as S-VOLs.
• Volumes that other software applications are using for pairs or migration plans.
• Deduplication system data volume.

Emulation type

OPEN-V

Path definitions

Required. The LU path definitions or a namespace on the NVM subsystem with an NVM subsystem port added for NVMe must be defined.

Not required for cascaded pairs and pairs with the clone attribute.

Volume type

Logical volumes (LDEVs).

To maintain performance levels, use the following configurations:

• Place normal volumes and pool-VOLs in separate parity groups (see Thin Image licensed capacity requirements).
• Ensure that pool-VOLs consist of LDEVs from more than one parity group.

You cannot specify the following volumes as HTI pool-VOLs:

• LDEV whose LDEV status in HDvM - SN is other than Normal, Correction Access, or Copying. In CCI, use the raidcom get ldev command to check the volume type.
• Volumes that are already being used as HTI P-VOL or S-VOLs.
• Volumes that are already contained in HTI, HDP, HDT, or active flash pools.
• Volumes used as migration plans or pair volumes for another product.
• Volumes for which you have used the Data Retention Utility to set Read Only, Protect, or S-VOL Disable attributes.
• Command device volumes.
• GAD volumes with the reservation attribute.
• GAD volumes for quorum disks.
• External volumes with the Data Direct Mapping attribute.
• DP-VOLs with the Data Direct Mapping attribute.

Note: The following restrictions apply to volumes used in the same data pool:

• Volumes must be in the same resource group.
• External pool-VOLs must have the same cache mode, either enabled or disabled.
• When using both internal and external volumes, the external volumes must have cache mode enabled.

Emulation type

OPEN-V

RAID level

Data drive type

You can use SSD, FMD, and HDD.*

Regardless of the type of the volume (internal volume or external volume), you can use pool-VOLs with different drive types in the same pool. For best performance, use pool-VOLs with the same drive type in the same pool.

For more information about the data drive type, see Pool creation and data drive type priority.

CLPR

Registering pool-VOLs to Cache Logical Partition Numbers (CLPRs) in pools:

You can register pool-VOLs assigned to different CLPRs in a pool.

Changing CLPRs:

You can change CLPRs in the parity group belonging to the pool-VOL. In this case, regardless of the CLPR in the pool-VOL, the CLPR ID in the parity must be the same as that of the P-VOL that you are using.

Pool limit

1,024

Volume capacity

8 GB to 4 TB

Path definition

A volume on which an unnecessary path is defined or a volume that is assigned to a namespace for NVMe cannot be specified as a pool-VOL.