Managing Serviceguard Fifteenth Edition, reprinted May 2008

Understanding Serviceguard Hardware Configurations
Redundant Network Components
Chapter 242
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.
• 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 such as Serviceguard
Extension for Oracle RAC (SGeRAC); 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.
• Deploying applications in this environment requires careful
consideration; see “Implications for Application Deployment” on
page 192.
• 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).