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

Customize the package configuration file as appropriate to your application. Be sure to include
the pathname of the control script (/etc/cmcluster/pkgname/pkgname.cntl) for the
RUN_SCRIPT and HALT_SCRIPT parameters.
3. In the <pkgname>.ascii file, list the node names in the order for which the package is to
fail over. It is recommended for performance reasons, that the package fail over locally first,
then to the remote data center.
The failover_policy parameter for a Metrocluster package can be set to
site_preferred. This value implies that during a Metrocluster package failover, while
selecting nodes from the list of the node_name entries, the Metrocluster package will first fail
over to the nodes that belong to the site of the node it last ran on, rather than the nodes that
belong to the other site. To use this policy the underlying cluster must be configured with sites
and each cluster nodes should be associated to a site. For information on configuring the
failover policy to site_preferred, see “Site Aware Failover Configuration” (page 26).
NOTE: If using the EMS disk monitor as a package resource, do not use NO_TIMEOUT.
Otherwise, package shutdown will hang if there is not access from the host to the package
disks.
This toolkit may increase package startup time by 5 minutes or more. Packages with many
disk devices will take longer to start up than those with fewer devices due to the time needed
to get device status from the EMC Symmetrix disk array. Clusters with multiple packages that
use devices on the EMC Symmetrix disk array will cause package startup time to increase
when more than one package is starting at the same time.
The value of RUN_SCRIPT_TIMEOUT in the package ASCII file should be set to NO_TIMEOUT
or to a large enough value to take into consideration the extra startup time due to getting
status from the Symmetrix.
4. Create a package control script.
# cmmakepkg -s pkgname.cntl
Customize the control script as appropriate to your application using the guidelines in the
Managing Serviceguard user’s guide. Standard Serviceguard package customizations include
modifying the VG, LV, FS, IP, SUBNET, SERVICE_NAME, SERVICE_CMD, and
SERVICE_RESTART parameters. Be sure to set LV_UMOUNT_COUNT to 1 or greater.
5. Add customer-defined run and halt commands in the appropriate places according to the
needs of the application. See the Managing Serviceguard user’s guide for more information
on these functions.
6. In the package_name.ascii file, list the node names in the order in which you want the
package to fail over. It is recommended, for performance reasons, that the package fail over
locally first, then to the remote data center. For the MAX_CONFIGURED_PACKAGES parameter,
the minimum value is 0 and maximum default value is 150 (depending on the number of
packages that will run on the cluster).
7. Copy the environment file template /opt/cmcluster/toolkit/SGSRDF/
srdf.env to the package directory, naming it pkgname_srdf.env:
# cp /opt/cmcluster/toolkit/SGSRDF/srdf.env \
/etc/cmcluster/pkgname/pkgname_srdf.env
Building a Metrocluster Solution with EMC SRDF 273