Managing HP Serviceguard for Linux, Eighth Edition, March 2008

Planning and Documenting an HA Cluster
Package Configuration Planning
Chapter 4120
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 (the node the packages move to). 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.
NOTE To prevent an operator from accidentally activating volume groups on
other nodes in the cluster, versions A.11.16.07 and later of Serviceguard
for Linux include a type of VG activation protection. This is based on the
“hosttags” feature of LVM2.
This feature is not mandatory, but HP strongly recommends you
implement it as you upgrade existing clusters and create new ones. See
“Enabling VG Activation Protection” on page 163 for instructions.
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: