Building Disaster Recovery Serviceguard Solutions Using Continentalclusters for Linux B.12.00.00

After the notification is received, and it is determined that the by using the recovery checklist that
recovery is required, ensure the following:
• The data used by the application is in usable state. Usable state means the data is consistent
and recoverable, even though it might not be current.
• The secondary devices are in read-write mode. If you are using database or software data
replication ensure 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 activation tag is used, run the following commands from a node in the recovery cluster
on all the volume groups that are used by the recovery packages:
# export hostid=$(vgs --noheadings -o +tags $vg | awk '{print $8}')
# vgchange --deltag $hostid <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>
For a sample recovery checklist, see the section “Recovery Checklist” (page 54)
Using cmrecovercl to recover the recovery groups
CAUTION: When the Continentalclusters is in recovery enabled state, do not start up the recovery
packages using the cmrunpkg command. Instead use the cmrecovercl command to start up
the recovery packages.
Previewing the storage preparation
Before starting up the recovery groups, it is recommended to use the cmdrprev command to
preview the storage failover process. If the cmdrprev commands exits with failure, then it implies
that the storage cannot be prepared successfully. Examine the output of the cmdrprev command
to take appropriate action. The cmdreprev command is supported only in Continentalclusters
configuration that uses Metrocluster supported array based replication.
Recovering the entire cluster after a cluster alarm
After the cmdrprev command succeeds, use the following commands to start the failover recovery
process if the Continentalclusters is in an alarm state:
# cmrecovercl
NOTE: The cmrecovercl command skips recovery of recovery groups in maintenance mode.
Performing recovery in case of disaster 25