Building Disaster Recovery Serviceguard Solutions Using Metrocluster with 3PAR Remote Copy

6 Administering a Metrocluster with 3PAR Remote Copy
Administering a cluster that uses Metrocluster 3PAR Remote Copy
While the package is running, a manual storage failover on Remote Copy volume group outside
of Metrocluster with 3PAR Remote Copy software can cause the package to halt due to unexpected
condition of the 3PAR Remote Copy virtual volumes. HP recommends that no manual storage
failover be performed while the package is running.
If the Remote Copy replication was stopped due to link failures, you can manually start the
replication even while the package is running. You do not have to manually start the replication
if the auto_recover option is set for the Remote Copy volume group.
Viewing the Remote Copy volume group details
To associate the Remote Copy volume group name with the package, run the cmgetpkgenv
command:
# cmgetpkgenv <pkg_name>
To list the various properties of 3PAR Remote Copy volume group, run the CLI command
showrcopy.
The Remote Copy volume group details can also be viewed using HP 3PAR Management Console.
Normal maintenance
There might be situations when the package has to be taken down for maintenance purposes
without having the package move to another node. The following procedure is recommended for
normal maintenance of the Metrocluster with 3PAR Remote Copy package.
1. Stop the package with the appropriate Serviceguard command.
# cmhaltpkg pkgname
2. Perform the maintenance.
3. Distribute the package configuration changes, if any.
# cmapplyconf -P pkgname.config
4. Start the package with the appropriate Serviceguard command.
# cmmodpkg -e pkgname
The cluster considers a planned node maintenance the same as a failure. If you take a node
down for maintenance, package failover and quorum calculation is based on the remaining
nodes. Make sure that nodes are taken down evenly at each site, and that enough nodes
remain on-line to form a quorum if a failure occurs.
Remote Copy link failure and resume modes
When the link fails, snapshots are created for all primary volumes, but no snapshots are created
for 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 to resynchronize the secondary volume with the primary volume.
Upon Remote Copy links recovery, 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 issuing the
startrcopygroup command on the system that holds the primary group to resynchronize the
primary and secondary groups.
Administering a cluster that uses Metrocluster 3PAR Remote Copy 49