Designing Disaster Recovery Clusters using Metroclusters and Continentalclusters, Reprinted October 2011 (5900-1881)

Using the Recovery Command to Switch All Packages
If Metrocluster Continuous Access P9000 or XP, or Metrocluster Continuous Access EVA, or
Metrocluster with EMC SRDF, or Metrocluster with 3PAR Remote Copy is not the chosen data
replication technology, use the following steps before executing the Continentalclusters recovery
command, cmrecovercl.
Once notification is received and there is coordination between the sites in a recovery pair, (For
a sample worksheet, see “Documenting the Recovery Procedure” (page 91)), and have determined
that moving the package is necessary:
• Check to make sure the data used by the application is in usable state. Usable state means
the data is consistent and recoverable, even though it may not be current.
• Check to make sure the secondary devices are in read-write mode. If you are using database
or software data replication make sure the data copy at the recovery site is in read-write mode
as well.
• If LVM and physical data replication are used, the ID of the primary cluster is also replicated
and written on the secondary devices in the recovery site. The ID of the primary cluster must
be cleared and the ID of the recovery cluster must be written on the secondary devices before
they can be used.
If LVM exclusive-mode is used, issue the following commands from a node in the recovery
cluster on all the volume groups that are used by the recovery packages:
# vgchange -c n <volume group name>
# vgchange -c y <volume group name>
If LVM shared-mode (SLVM) is used, from a node in the recovery cluster, issue the following
commands:
# vgchange -c n -S n <volume group name>
# vgchange -c y -S y <volume group name>
• If VxVM and physical data replication are used, the host name of a node in the primary cluster
is the host name of the last owner of the disk group. It is also replicated and written on the
secondary devices in the recovery site. The host name of the last owner of the disk group must
be cleared out before the secondary devices can be used.
If VxVM is used, issue the following command from a node in the recovery cluster on all the
disk groups that are used by the recovery packages:
# vxdg deport <disk group name>
To Start the Failover Process
Use the following commands to start the failover process:
# cmrecovercl
If a notification defined in a CLUSTER_ALARM statement in the configuration file is not received,
but a CLUSTER_ALERT and the remote site has confirmed the need to fail over has been received,
then override the disabled cmrecovercl command by using the -f forcing option:
# cmrecovercl -f
Use this command only after positive confirmation from the remote site. The cmrecovercl command
will skip recovery for recovery groups in maintenance mode.
In a multiple recovery pair configuration where more than one primary cluster is sharing the same
recovery cluster, runningcmrecovercl without any option will attempt to recover packages for
all of the recovery groups of the configured primary clusters. Recovery can also be done in this
multiple recovery pair case on a per cluster basis by using option -c.
# cmrecovercl -c <PrimaryClusterName>
Switching to the Recovery Packages in Case of Disaster 95