Designing Disaster Tolerant High Availability Clusters, 10th Edition, March 2003 (B7660-90013)

Cascading Failover in a Continental Cluster
Data Replication Procedures
Chapter 8390
Scenario 3—Entire Primary Cluster Fails
In this scenario, the assumption is that both primary site and secondary
site fail at the same time or very close to each other. This scenario is
illustrated in Figure 8-12.
Figure 8-12 Failure of Entire Primary Cluster
Failover from Primary Cluster to Recovery Cluster
After reception of the ContinentalClusters alerts and alarm, the
administrators at the recovery site follow the prescribed processes and
recovery procedures to start the protected applications on the recovery
cluster. Note that data corruption may occur in situation where a
disaster occurs at the primary cluster while the data refresh from
secondary Symmetrix to the recovery Symmetrix is in progress. The
data in the R2 devices in the recovery Symmetrix is not usable. The data
can be recovered by restoring an old copy of the data from the BCV
devices in the recovery Symmetrix. Execute the following commands to
restore the data:
1. Restore the data from the BCV to the R2 devices in the recovery
Symmetrix:
# symmir -g <recsymdevgrpname> -full restore
2. Use the following command to check the data restore progress. If the
pair state is “Synchronized,” the data restore is complete.
# symmir -g <recsymdevgrpname> query