Managing Serviceguard Sixteenth Edition, March 2009

NOTE: As of the date of this manual, the Framework for HP Serviceguard Toolkits deals
specifically with legacy packages.
Logical Volume and File System Planning
NOTE: LVM Volume groups that are to be activated by packages must also be defined
as cluster-aware in the cluster configuration file. See “Cluster Configuration Planning
” (page 137). Disk groups (for Veritas volume managers) that are to be activated by
packages must be defined in the package configuration file, described below.
You may need to use logical volumes in volume groups as part of the infrastructure
for package operations on a cluster. When the package moves from one node to another,
it must be able to access data residing on the same disk as on the previous node. This
is accomplished by activating the volume group and mounting the file system that
resides on it.
In Serviceguard, high availability applications, services, and data are located in volume
groups that are on a shared bus. When a node fails, the volume groups containing the
applications, services, and data of the failed node are deactivated on the failed node
and activated on the adoptive node. In order for this to happen, you must configure
the volume groups so that they can be transferred from the failed node to the adoptive
node.
As part of planning, you need to decide the following:
• What volume groups are needed?
• How much disk space is required, and how should this be allocated in logical
volumes?
• What file systems need to be mounted for each package?
• Which nodes need to import which logical volume configurations?
• If a package moves to an adoptive node, what effect will its presence have on
performance?
Create a list by package of volume groups, logical volumes, and file systems. Indicate
which nodes need to have access to common file systems at different times.
HP recommends that you use customized logical volume names that are different from
the default logical volume names (lvol1, lvol2, etc.). Choosing logical volume names
that represent the high availability applications that they are associated with (for
example, lvoldatabase) will simplify cluster administration.
To further document your package-related volume groups, logical volumes, and file
systems on each node, you can add commented lines to the /etc/fstab file. The
following is an example for a database application:
# /dev/vg01/lvoldb1 /applic1 vxfs defaults 0 1 # These six entries are
# /dev/vg01/lvoldb2 /applic2 vxfs defaults 0 1 # for information purposes
# /dev/vg01/lvoldb3 raw_tables ignore ignore 0 0 # only. They record the
160 Planning and Documenting an HA Cluster