Managing Serviceguard Nineteenth Edition, Reprinted June 2011

• Because Veritas Cluster File System from Symantec (CFS) requires link-level traffic communication
(LLT) among the nodes, Serviceguard cannot be configured in cross-subnet configurations with
CFS alone.
But CFS is supported in specific cross-subnet configurations with Serviceguard and HP add-on
products; see the documentation listed below.
• Each package subnet must be configured with a standby interface on the local bridged net.
The standby interface can be shared between subnets.
• You must not set the HP-UX network parameter ip_strong_es_model in a cross-subnet
configuration. Leave it set to the default (0, meaning disabled); Serviceguard does not support
enabling it for cross-subnet configurations. For more information about this parameter, see
“Tuning Network and Kernel Parameters” (page 162) and “Using a Relocatable Address as
the Source Address for an Application that is Bound to INADDR_ANY” (page 335).
• Deploying applications in this environment requires careful consideration; see “Implications
for Application Deployment” (page 146).
• 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 27) 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 “Obtaining Cross-Subnet Information” (page 181), “About Cross-Subnet Failover”
(page 145) and (for legacy packages only) “Configuring Cross-Subnet Failover” (page 295).
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.
30 Understanding Serviceguard Hardware Configurations