Managing Serviceguard Eighteenth Edition, September 2010

• You should not use the wildcard (*) for node_name in the package configuration
file, as this could allow the package to fail over across subnets when a node on the
same subnet is eligible, and failing over across subnets can take longer.
List the nodes in order of preference rather than using the wildcard.
• You should configure IP monitoring for each subnet; see “Monitoring LAN
Interfaces and Detecting Failure: IP Level” (page 98).
Restrictions
The following restrictions apply:
• All nodes in the cluster must belong to the same network domain (that is, the
domain portion of the fully-qualified domain name must be the same).
• The nodes must be fully connected at the IP level.
• A minimum of two heartbeat paths must be configured for each cluster node.
• There must be less than 200 milliseconds of latency in the heartbeat network.
• Each heartbeat subnet on each node must be physically routed separately to the
heartbeat subnet on another node; that is, each heartbeat path must be physically
separate:
— The heartbeats must be statically routed; static route entries must be configured
on each node to route the heartbeats through different paths.
— Failure of a single router must not affect both heartbeats at the same time.
• IPv6 heartbeat subnets are not supported in a cross-subnet configuration.
• IPv6–only and mixed modes are not supported in a cross-subnet configuration.
For more information about these modes, see “About Hostname Address Families:
IPv4-Only, IPv6-Only, and Mixed Mode” (page 139).
• 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 223)
and “Using a Relocatable Address as the Source Address for an Application that
is Bound to INADDR_ANY” (page 435).
• Deploying applications in this environment requires careful consideration; see
“Implications for Application Deployment” (page 202).
42 Understanding Serviceguard Hardware Configurations