Managing HP Serviceguard for Linux, Tenth Edition, September 2012

• Deploying applications in this environment requires careful consideration; see
“Implications for Application Deployment” (page 152).
• cmrunnode will fail if the “hostname LAN” is down on the node in question.
(“Hostname LAN” refers to the public LAN on which the IP address that the node’s
hostname resolves to is configured).
• If a monitored_subnet is configured for PARTIAL monitored_subnet_access
in a package’s configuration file, it must be configured on at least one of the nodes
on 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 25) 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 151), “Obtaining
Cross-Subnet Information” (page 183), and (for legacy packages only) “Configuring
Cross-Subnet Failover” (page 279).
See also the white paper Technical Considerations for Creating a Serviceguard Cluster
that Spans Multiple IP Subnets, which you can find at the address below. This paper
discusses and illustrates supported configurations, and also potential mis-configurations.
IMPORTANT: Although cross-subnet topology can be implemented on a single site, it
is most commonly used by extended-distance clusters. For more information about such
clusters, see the latest edition of the HP Serviceguard Extended Distance Cluster for Linux
Deployment Guide on docs.hp.com under High Availability —> Serviceguard
for Linux.
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.
Redundant Disk Storage 29