Consistency and snapshot groups
Consistency groups and snapshot groups are groups of pairs for which you can simultaneously perform pair tasks on all pairs within the group.
A consistency group can include Thin Image (HTI), ShadowImage (SI), and ShadowImage for Mainframe (SIz) pairs. Use consistency groups to split the Thin Image pairs that are defined in the group. Splitting the pairs using the group assures data consistency at the time the VSP family storage system receives the request.
A snapshot group is a group of only Thin Image pairs. Use consistency or snapshot groups to perform Thin Image tasks on all of the pairs within the group. You define Thin Image pairs to a snapshot group when you create the pairs.
The following table shows the differences between consistency groups and snapshot groups.
|
Item |
Consistency group |
Snapshot group |
|
Pair limit per group (VSP F1500, VSP G1x00, VSP F350, VSP F370, VSP F700, VSP F900 VSP G350, VSP G370, VSP G700, VSP G900) |
8,192 |
8,192 |
|
Pair limit per group (VSP G130) |
1,024 |
8,192 |
|
Limit |
2,048 |
2,048 |
|
Data consistency |
Guaranteed |
Not guaranteed |
|
Software application from which you can define pairs |
HTI, SI, and SIz |
HTI |
For more information about defining TC pairs in consistency groups, see the TrueCopy User Guide.
For more information about defining UR pairs in consistency groups, see the Universal Replicator User Guide.
For more information about defining SI pairs in consistency groups, see the ShadowImage User Guide.