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

d. Uncomment the DEVICE_GROUP variable and set them to the Symmetrix device group
names given in the ’symdg list’ command. The DEVICE_GROUP variable may also contain
the consistency group name if using a M by N configuration.
e. Uncomment the RETRY and RETRYTIME variables. The defaults should be used for the
first package. The values should be slightly different for other packages. RETRYTIME
should increase by two seconds for each package. The product of RETRY * RETRYTIME
should be approximately five minutes. These variables are used to decide how often and
how many times to retry the Symmetrix status commands.
For example, if there are three packages with data on a particular Symmetrix pair
(connected by SRDF), then the values for RETRY and RETRYTIME might be as follows:
Table 24 RETRY and RETRYTIME Values
RETRYTIMERETRY
5 seconds60 attemptspkgA
7 seconds43 attemptspkgB
9 seconds33 attemptspkgC
f. Uncomment the CLUSTER_TYPE variable and set it to “continental”.
g. Uncomment the RDF_MODE and set it to “async” or “sync” as appropriate to your
application.
10. Edit the remaining control script variables (VG, LV, FS, IP, SUBNET, SERVICE_NAME,
SERVICE_CMD and SERVICE_RESTART) according to the needs of the application as it runs
on the source disk site. See the Managing Serviceguard manual for more information on these
variables.
11. Add customer-defined run and halt commands in the appropriate places according to the
needs of the application. See the Serviceguard manual for more information on these functions.
12. Distribute EMC SRDF package configuration, environment, and control script files to other
nodes in the source disk site by using ftp, rcp or scp.
# rcp -p /etc/cmcluster/<pkg_name>/<pkg_name>.cntl \
other_node:/etc/cmcluster/<pkg_name>/<pkg_name>.cntl
When using ftp, be sure to make the file executable on any destination systems.
13. Verify that each host in both clusters in the Continentalclusters has the following files in the
directory /etc/cmcluster/<pkg_name>:
• <pkg_name>.cntl (EMC SRDF package control script)
• <pkg_name>.conf (Serviceguard package ASCII config file)
• <pkg_name>.sh (Package monitor shell script, if applicable)
• <pkg_name>_srdf.env (Metrocluster EMC SRDF environment file)
14. Split the SRDF logical links for the disks associated with the application package. See the
script Samples/pre.cmqueryfor an example of how to automate this task. The script must
be customized with the Symmetrix device group names.
15. Apply the Serviceguard configuration using the cmapplyconf command or SAM.
16. Using standard Serviceguard commands (cmruncl, cmhaltcl, cmrunpkg, cmhaltpkg),
test the source disk site for cluster and package startup and failover.
17. Restore the SRDF logical links for the disks associated with the application package. See the
script Samples/post.cmapply (after target disk site is completed in next section) for an
example of how to automate this task. The script must be customized with the Symmetrix device
group names.
Building Continentalclusters Solution with EMC SRDF 301