Designing Disaster Tolerant High Availability Clusters, 10th Edition, March 2003 (B7660-90013)

Cascading Failover in a Continental Cluster
Data Replication Procedures
Chapter 8 385
The <recbcvdev_textfile> is a file that contains a list of the standard
device and BCV device pair in the recovery Symmetrix.
2. Freeze the application I/O if the application is writing data to the R1
devices in the primary Symmetrix. The method of freezing the I/O is
application dependent.
3. Split the BCV/R1 devices in the secondary Symmetrix from the
mirror group and start synchronization with the R2 devices in the
recovery Symmetrix:
# symmir -g <secsymdevgrpname> split
4. Resume the application I/O to the R1 devices in the primary
Symmetrix if needed. The method of resuming the I/O is application
dependent.
5. Incrementally establish the SRDF volume pairs between the
secondary Symmetrix and the recovery Symmetrix. The data is
synchronized from the secondary Symmetrix BCV/R1 devices to the
recovery Symmetrix R2 devices
# symrdf -g <secsymdevgrpname> est -bcv
6. Use the following command to check the data synchronization from
the BCV/R1 devices to the R2 devices. If the "RDF Pair STATE"
column shows the state “Synchronized” for all the devices, the
copying completed.
# symrdf -g <secsymdevgrpname> query -bcv
7. Once the copy completes, split the SRDF link between the secondary
Symmetrix and the recovery Symmetrix:
# symrdf -g <secsymdevgrpname> split -bcv
8. Re-establish the BCV devices in the recovery Symmetrix as mirrors
of the standard devices:
# symmir -f <recbcvdev_textfile> -sid <recsymid> est
9. Re-establish the BCV/R1 devices in the secondary Symmetrix as
mirrors of the standard devices:
# symmir -g < secsymdevgrpname > est
Refer to the sample script secrefreshrec in the
/opt/cmcluster/toolkit/SGSRDF/cascade/Samples directory for
example of how these commands are used. This script is designed to run
only on a node that connects to the secondary Symmetrix.