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

# cmruncl
10. Verify the data for data consistency and currency.
Scenario 2
The primary site Symmetrix experienced a catastrophic hardware failure and all data was lost on
the array. After the reception of the Continentalclusters alerts and alarm, the administrators at the
recovery site follow prescribed processes and recovery procedures to start the protected applications
on the target disk site. The Continentalclusters package control file will invoke Metrocluster with
EMC SRDF to evaluate the status of the Symmetrix SRDF paired volumes. Since the systems at the
primary site are accessible, but the Symmetrix is not, the control file will evaluate the paired volumes
with a local status of “failed over”. The control file script is programmed to handle this condition
and will enable the volume groups, mount the logical volumes, assign floating IP addresses and
start any processes as coded into the script. After the primary site Symmetrix is repaired and
configured, use the following procedure to move the application package back to the primary site.
1. Manually create the Symmetrix device groups and gatekeeper configurations device groups.
Re-run the scripts mk3symgrps* and mk4gatekpr* which do the following:
# date >ftsys1.group.list
# symdg create -type RDF1 pkgCCA_r1
# symld -g pkgCCA_r1 add pd /dev/rdsk/c7t0d0
# symgate define pd /dev/rdsk/c7t15d0
# symgate define pd /dev/rdsk/c7t15d1
# symgate -g pkgCCA_r1 associate pd /dev/rdsk/c7t15d0
2. Halt the Continentalclusters recovery packages at the recovery site.
# cmhaltpkg <pkg_name>
This will halt any applications, remove any floating IP addresses, unmount file systems and
deactivate volume groups as programmed into the package control files. The status of the
paired volumes will be SPLIT at both the recovery and primary sites.
3. Halt the Cluster, which also halts the monitor package ccmonpkg.
4. Start the cluster at the primary site. Assuming they have been properly configured the
Continentalclusters primary packages should not start. The monitor package should start
automatically. Since the paired volumes have a status of SPLIT at both the primary and recovery
sites, the EMC views the two halves as unmirrored.
5. Issue the following command:
# symrdf -g pkgCCB_r1 failback
Since the most current data will be at the remote or recovery site, this command to synchronize
from the remote site). Wait for the synchronization process to complete before progressing to
the next step. Failure to wait for the synchronization to complete will result in the package
failing to start in the next step.
6. Manually start the Continentalclusters primary packages at the primary site using
# cmrunpkg <PKG_NAME>
The control script is programmed to handle this case. The control script recognizes the paired
volume is synchronized and will proceed with the programmed package startup.
7. Verify the device group is synchronized.
# symrdf list
8. Ensure that the monitor packages at the primary and recovery sites are running.
Building Continentalclusters Solution with EMC SRDF 307