Managing HP Serviceguard for Linux Ninth Edition, April 2009

the node_name list for that package. Conversely, if all of the subnets that are being
monitored for this package are configured for PARTIAL access, each node on the
node_name list must have at least one of these subnets configured.
— As in other configurations, a package will not start on a node unless the subnets
configured on that node, and specified in the package configuration file as
monitored subnets, are up.
NOTE: See also the Rules and Restrictions (page 30) that apply to all cluster
networking configurations.
For More Information
For more information on the details of configuring the cluster and packages in a
cross-subnet context, see “About Cross-Subnet Failover” (page 141), “Obtaining
Cross-Subnet Information” (page 173), and (for legacy packages only) “Configuring
Cross-Subnet Failover” (page 259).
IMPORTANT: Although cross-subnet topology can be implemented on a single site,
it is most commonly used by extended-distance clusters.
Design and configuration of such clusters are covered in the disaster-tolerant
documentation delivered with Serviceguard. For more information, see Understanding
and Designing Serviceguard Disaster Tolerant Architectures at http://www.docs.hp.com
-> High Availability.
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.
34 Understanding Hardware Configurations for Serviceguard for Linux