HP StorageWorks EVA Virtualization Adapter administrator guide (5697-0177, October 2009)

Table Of Contents
4 Failover and failback with SRM
This section discusses failover and failback with SRM. It also provides a scenario as a guide for the
manual process of failback.
Failover
Failover occurs when an SRM recovery plan is executed, and the SRM recovery plan is configured
to fail over SRM protection groups that use replicated EVA vdisks as a datastore.
During normal operation, the replication path is from a protected site (local site) to a recovery site
(remote site). When a failure occurs at the local site (due to hardware failure or the entire site loss) a
failover occurs and the replication path is reversed from the recovery site to the protected site. With
HP EVA Virtualization Adapter and SRM, the failover process is an automated feature and the process
is executed using a recovery plan located at the recovery site.
NOTE:
HP recommends that the user sets the DR group write mode to
Sync
before performing a planned
failover. This will ensure:
the data is current
the failover does not result in full-copy (reverse copy) from secondary site to primary site vdisks
Failback
Failback is the process of setting the replication environment back to its original state at the protected
site (local site) prior to failover. Failback can be managed as a normal server migration process.
However, managing the failback process with SRM is a manual process and the steps vary with
respect to the degree of failure at the protected site (local site). For example, the failover could have
been due to a hardware error or the loss of the entire data center.
Failback scenario with SRM
In the following failback scenario, SRM is used as a failback tool to return a protected site (Site A) to
its original state after executing a recovery plan (R1) at a recovery site (Site B).
To execute a failback manually:
1. Delete recovery plan at the recovery site (Site B).
2. If the protected site (Site A) still has HP Continuous Access EVA or data replication groups con-
figured for the protection groups (P1) in recovery plan (R1), delete protection groups (P1) at the
protected site. This could be the case if some of the hardware at the protected site was not replaced
after a disaster and you will be employing the existing hardware. If new hardware has been in-
stalled, it is not necessary to delete existing protection groups.
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