Managing HP Serviceguard for Linux, Seventh Edition, July 2007

Planning and Documenting an HA Cluster
Cluster Configuration Planning
Chapter 4 109
NOTE Heartbeat IP addresses must be on the same subnet on
each node, and must be IPv4 addresses.
For information about changing the configuration
online, see “Changing the Cluster Networking
Configuration while the Cluster Is Running” on
page 256.
Heartbeat configuration requirements:
The cluster needs at least two network interfaces for
the heartbeat in all cases, using one of the following
configurations:
• two heartbeat subnets; or
• one heartbeat subnet using bonding in high
availability mode (or mode 1) with two slaves.
For information about changing the configuration
online, see “Changing the Cluster Networking
Configuration while the Cluster Is Running” on
page 256.
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 time-out 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.