Building Disaster Recovery Serviceguard Solutions Using Continentalclusters for Linux B.01.00.00

Remote Copy Link Failure and Resume Modes
When the link is failed, snapshots are created for all the primary volumes, but not for the secondary
volumes while replication is stopped. When replication is restarted for the volume, all differences
between the base volume and the snapshot taken when the replication was stopped are sent over
in order to resynchronize the secondary volume with the primary volume.
When the Remote Copy links are recovered, HP 3PAR Remote Copy automatically restarts the
replication if the auto_recover policy is set. If the auto_recover policy is not set, when the
links are restored, you can copy any writes from the primary to the secondary groups by running
the startrcopygroup command on the system that holds the primary group to resynchronize
the primary and secondary groups.
Restoring replication after a failover
When the primary package fails over to the remote site and the links are not up or the primary
storage system is not up, Metrocluster runs the setrcopygroup failover command. This
command changes the role of the Remote Copy volume group on the storage system in the recovery
site from Secondary to Primary-Rev. In this role, the data is not replicated from the recovery
site to the primary site. After the links are restored or the primary storage system is restored,
manually run the setrcopygroup recover command on the storage system in the recovery
site to resynchronize the data from the recovery site to the primary site. This results in the change
of the role of the Remote Copy volume group on the storage system in the primary site from "Primary"
to "Secondary-Rev".
CAUTION: When the roles are Secondary-Rev and Primary-Rev, a disaster on the recovery
site results in a failure of the Metrocluster package. To avoid this, immediately halt the package
on the recovery site and start it up on the primary site. This will restore the role of the Remote Copy
volume group to its original role of Primary and Secondary.
50 Administering Continentalclusters