Managing Serviceguard Eighteenth Edition, September 2010

IP addresses for a given heartbeat path are
usually on the same subnet on each node, but it
is possible to configure the heartbeat on multiple
subnets such that the heartbeat is carried on one
subnet for one set of nodes and another subnet
for others, with the subnets joined by a router.
This is called a cross-subnet configuration, and
in this case at least two heartbeat paths must be
configured for each cluster node. In addition,
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). See
“Cross-Subnet Configurations” (page 41) for
more information.
NOTE: Limitations:
• 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 under “Cross-Subnet Configurations”
(page 41) for more information.
• IPv6 heartbeat subnets are not supported in
a cross-subnet configuration.
Considerations for CVM:
• For Veritas CVM 4.1 or later, multiple
heartbeats are permitted, and you must
configure either multiple heartbeat subnets
or a single heartbeat subnet with a standby.
HP recommends multiple heartbeats.
• You cannot change the heartbeat
configuration while a cluster that uses CVM
is running.
• You cannot use an IPv6 heartbeat subnet
with CVM or CFS.
154 Planning and Documenting an HA Cluster