IBM XIV Storage System Copy Services and Migration

there are certain additional constraints, such as same role, target, schedule, and so on). Theslave volume is automatically added to the consistency group on the remote XIV system.In Figure 4-34, three active volume couplings that have completed initialization have beenmoved into the active mirrored consistency group.SITE 1 SITE 2ProductionDR Test/Recovery ServersConsistency Group PeerPrimary Designation (P)Master Role (M)P/MCGCoupling/MirrorActiveS/SConsistency Group PeerSecondary Designation (S)Slave Role (S)Figure 4-34 Consistency group mirror couplingOne or more additional mirrored volumes may be added to a mirrored consistency group at alater time in the same way.It is also important to realize that in a CG all volumes have the same role. Also, consistencygroups are handled as a single entity and, for example, in asynchronous mirroring, a delay inreplicating a single volume affects the status of the entire CG.4.4.7 Normal operation: volume mirror coupling and CG mirror couplingXIV mirroring normal operation begins after initialization has completed successfully and allactual data on the master volume at the time of activation has been copied to the slavevolume. During normal operation, a consistent set of data is available on the slave volumes.Normal operation, statuses, and reporting differ for XIV synchronous mirroring and XIVasynchronous mirroring. Refer to Chapter 5, “Synchronous Remote Mirroring” on page 125,and Chapter 6, “Asynchronous Remote Mirroring” on page 149, for details.98 IBM XIV Storage System: Copy Services and Migration