The attributes of Thin Image Advanced consistency groups, such as the pair limit and pair type, have usage requirements. Review these requirements before creating consistency groups.
|
Item |
Requirement |
|---|---|
|
Snapshot group name |
Maximum of 32 characters. You can change the snapshot group name by using CCI command. A snapshot name is also used to operate on a group specified as a consistency group. |
|
Consistency group ID |
Value: 0 to 2,047 With SI, SIz, HTI Advanced, and HTI, you can create up to 2,048 consistency groups in a storage system. To have the pair that you are creating belong to a consistency group, use the raidcom add snapshot command with the - snap_mode cascade CTG option specified. An unassigned number from 0 to 2,047 is automatically assigned.* Consistency group ID is displayed in the following windows in HDvM - SN:
|
|
Pair limit |
8,192 pairs per consistency group. |
| Pair type |
SI, SIz, HTI Advanced, and HTI pairs cannot co-exist in the same consistency group. For example, only HTI Advanced pairs can be defined in its own consistency group. |
|
* ShadowImage uses numbers from 0 to 127. Because of this, Thin Image Advanced assigns an unassigned number from 128 to 2,047 first. If there is no unassigned number from 128 to 2,047, then Thin Image Advanced assigns an unassigned number from 0 to 127. |
|
Consistency group restrictions:
- Thin Image Advanced pairs that share P-VOLs or are in higher and lower layers of a snapshot tree cannot be defined in the same consistency group. If they are defined in the same consistency group, the raidcom add snapshot command is rejected.
- A volume belonging to a consistency group and the following volumes cannot be
contained in the same consistency group:
- The pair volume (P-VOL or S-VOL) of a volume belonging to the consistency group
- A volume for which the P-VOL is the same as the volume belonging to the consistency group but that has a different MU number
- Thin Image Advanced does not support groups defined in the CCI configuration definition file (which is different from consistency groups).
- In Thin Image Advanced, you cannot create a pair by specifying a consistency group ID. For details about how to add multiple pairs to a consistency group, see Managing Thin Image Advanced pairs using CCI commands.