Managing HP Serviceguard for Linux, Eighth Edition, March 2008

Understanding Hardware Configurations for Serviceguard for Linux
Redundant Disk Storage
Chapter 2 33
Redundant Disk Storage
Each node in a cluster has its own root disk, but each node may also be
physically connected to several other disks in such a way that more than
one node can obtain access to the data and programs associated with a
package it is configured for. This access is provided by the Logical
Volume Manager (LVM). A volume group must be activated by no more
than one node at a time, but when the package is moved, the volume
group can be activated by the adoptive node.
NOTE As of release A.11.16.07, Serviceguard for Linux provides functionality
similar to HP-UX exclusive activation. This feature is based on LVM2
hosttags, and is available only for Linux distributions that officially
support LVM2.
All of the disks in the volume group owned by a package must be
connected to the original node and to all possible adoptive nodes for that
package.
Shared disk storage in Serviceguard Linux clusters is provided by disk
arrays, which have redundant power and the capability for connections
to multiple nodes. Disk arrays use RAID modes to provide redundancy.
Supported Disk Interfaces
The following interfaces are supported by Serviceguard for disks that are
connected to two or more nodes (shared data disks):
• MSA500 (Modular Smart Array) family Storage
• FibreChannel.
For information on configuring multipathing, see “Multipath for Storage”
on page 99.
Disk Monitoring
You can configure monitoring for disks and configure packages to be
dependent on the monitor. For each package, you define a package
service that monitors the disks that are activated by that package. If a