dictated by the frequency at which it is refreshed (that is data replicated from primary site to recovery site). The refresh process is shown in Figure 4.
Figure 4 - Data Refresh in Steady State
The following procedure describes the steps necessary to periodically copy the data from the secondary disk array to the recovery disk array while the application is running on the primary site.
1.Freeze the application I/O to prevent the application from writing data to the primary devices in the primary disk array. Note, the method of freezing the I/O is application dependent.
2.Make sure that data has replicated to the remote site before executing the next step.
3.Split the local mirror devices (device B’) in the secondary disk array from the primary replication group.
4.Resume the application I/O to the primary devices in the primary disk array if needed. Note, the method of resuming the I/O is application dependent.
5.Split the local mirror devices (device C’) in the recovery disk array from the secondary replication group. This is required to preserve an old copy of the data just in case a failure occurs during data synchronization between the secondary disk array and the recovery disk array that may cause data corruption on the destination devices in the recovery disk array.
6.Incrementally establish the secondary replication group (i.e. group between the secondary disk array and the recovery disk array). The data is copied from secondary disk array local mirror devices (device B’) to the recovery disk array secondary devices (device C).
7.Wait until the copying has completed before continuing to the next step.
8.Once the copy completes, split the data replication link between the secondary disk array and the recovery disk array.
9.
10.
Package Setup
Except for the following package setup instructions, packages for both primary and recovery follow the same steps as setting up a Continentalclusters package. See the Designing Disaster Tolerant High Availability Clusters manual for more information on setting up packages.
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