Managing HP Serviceguard A.11.20.10 for Linux, December 2012

Considerations for cross-subnet:
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, and 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 27).
NOTE: IPv6 heartbeat subnets are not supported in a
cross-subnet configuration.
NOTE: The use of a private heartbeat network is not
advisable if you plan to use Remote Procedure Call (RPC)
protocols and services. RPC assumes that each network
adapter device or I/O card is connected to a route-able
network. An isolated or private heartbeat LAN is not
route-able, and could cause an RPC request-reply, directed
to that LAN, to timeout without being serviced.
NFS, NIS and NIS+, and CDE are examples of RPC based
applications that are frequently used. Other third party and
home-grown applications may also use RPC services through
the RPC API libraries. If necessary, consult with the
application vendor.
STATIONARY_IP This node's IP address on each subnet that does not carry
the cluster heartbeat, but is monitored for packages.
NOTE: Any subnet that is configured in this cluster
configuration file as a SUBNET for IP monitoring purposes,
or as a monitored_subnet in a package configuration
file (or SUBNET in a legacy package; see “Package
Configuration Planning ” (page 100)) must be specified in
the cluster configuration file via NETWORK_INTERFACE and
either STATIONARY_IP or HEARTBEAT_IP. Similarly, any
subnet that is used by a package for relocatable addresses
should be configured into the cluster via
NETWORK_INTERFACE and either STATIONARY_IP or
HEARTBEAT_IP. For more information about relocatable
addresses, see “Stationary and Relocatable IP Addresses
and Monitored Subnets” (page 59) and the descriptions of
the package ip_ parameters (page 176).
If HOSTNAME_ADDRESS_FAMILY is set to IPV4 or ANY, a
stationary IP address can be either an IPv4 or an IPv6
address, with the exceptions noted below. If
HOSTNAME_ADDRESS_FAMILY is set to IPV6, all the IP
addresses used by the cluster must be IPv6 addresses.
If you want to separate application data from heartbeat
messages, define one or more monitored non-heartbeat
92 Planning and Documenting an HA Cluster