You can split pairs to store snapshot data or clone pairs for a consistency group using CCI (the consistency group pair-split function). This process explains how to use CCI’s consistency group pair-split to store snapshot data or clone pairs for each consistency group.
Note: If you cannot change the status of a pair in
a Thin Image consistency
group, the pairsplit command might return the error code
EX_EWSTOT (timeout), and end abnormally. For details, see Notes on using Thin Image primary volumes as TrueCopy, ShadowImage, or Universal Replicator pair volumes.
Use the following process to split Thin Image pairs to store snapshot data or clone pairs:
- (If the pairs are not created) Create two
Thin Image pairs and assign both pairs to the same consistency group. To do this, using
CCI, run the following
raidcom command twice using an option to specify the consistency group ID:
raidcom add snapshot
A pair is created and defined in a consistency group. This group is the target of the consistency group pair-split. The consistency group ID option you specified automatically enables the consistency group pair-split.
- Create the pair to store snapshot data for a group. To do this, using
CCI, specify the same consistency group ID as step 1 to run either of the following
raidcom commands:
raidcom modify snapshot -snapshot_data create
raidcom modify snapshot -snapshot_data clone
- The storage system receives the command. Then it stores the snapshot data for the consistency group that is the target of the consistency group pair-split, or clones pairs when a host issues a write request to the Thin Image pair's P-VOL that is assigned to the consistency group.
- A host issues a write request to the Thin Image pair’s P-VOL that is assigned to the consistency group.
- The pairs are split and the snapshot data is stored.