User's Guide

By default, the Metrocluster SRDF module includes only the Serviceguard volume group module.
If modules other than the Serviceguard modules need to be included, then they need to be
explicitly specified while creating the Metrocluster SRDF modular package configuration file.
The following example shows the package IP, the filesystem, and the monitor subnet module
included along with the Metrocluster SRDF module.
# cmmakepkg –m dts/mcsrdf –m sg/filesystem –m sg/monitor_subnet -m\
sg/package_ip temp.config
NOTE: Metrocluster is usually used with applications such as Oracle. So, the application
toolkit module must also be included when Metrocluster is used in conjunction with an
application.
For example:
When Metrocluster is used in conjunction with the Oracle toolkit, the Oracle toolkit module
and other required modules must also be included with the Metrocluster SRDF module. So,
following is the command that needs to be used:
# cmmakepkg –m dts/mcsrdf –m sg/filesystem -m sg/package_ip -m\
ecmt/oracle/oracle temp.config
2. Create a directory for storing the Metrocluster SRDF environment file on all the nodes where
the package is designated to run.
# mkdir /etc/cmcluster/<package_name>
3. In the newly created modular package configuration file, temp.config, specify the following:
a. The directory created previously for the dts/dts/dts_pkg_dir attribute.
b. The node names in the order in which the package needs to fail over.
To avoid an impact on performance, it is recommended to have the package first failover
to local nodes followed by failing over to the remote data center.
For the failover_policy parameter, Metrocluster failover packages can be configured
to use any of the Serviceguard defined failover policies. The site_preferred and
site_preferred_manual failover policies are introduced in Serviceguard specifically
for Metrocluster configurations. The site_preferred value implies that when a
Metrocluster package has to fail over, it will necessarily failover to a node within the
same site of the node it last ran on. Only when there is no other configured node available
within the same site, the package fails over to a node at the other site. The
site_preferred_manual failover policy provides automatic failover of packages
within a site and manual failover across sites. To use either of these policies 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 or
site_preferred_manual, see “Site Aware Failover Configuration” (page 26).
c. The value of run_script_timeout in the package configuration file. Set this value to
NO_TIMEOUT or to a large enough value to take into consideration the extra startup
time required to obtain status from the EMC Symmetrix disk array.
d. The package_type attribute. It must always be specified as failover.
e. The vg attribute. Set the required logical volume group name to the vg attribute.
f. If other Serviceguard modules are included, then specify values for the included module
attributes accordingly.
g. If any application module is included, then list values for the included module attributes
accordingly.
NOTE: If the EMS disk monitor is used as a package resource, then the NO_TIMEOUT value
must not be used. If used, the package shutdown hangs if there is no access from the host to
the package disks.
276 Building Disaster Recovery Serviceguard Solutions Using Metrocluster with EMC SRDF