Managing Serviceguard Fifteenth Edition, reprinted May 2008

Planning and Documenting an HA Cluster
Cluster Configuration Planning
Chapter 4162
separately to the heartbeat subnet on another node
(that is, each heartbeat path must be physically
separate).
See “Cross-Subnet Configurations” on page 41.
NOTE 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 under “Cross-Subnet
Configurations” on page 41 for more information.
Considerations for CVM:
• If you will be using 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.
• If you will be using CVM 3.5, however, you can only
use a single heartbeat subnet; in this case,
configure the heartbeat either with a standby LAN
or as a group of aggregated ports on each node. If
you use aggregated ports (APA), HP recommends
using Hot Standby mode to eliminate the single
point of failure (SPOF) that a single switch
represents. See Chapter 3 of the HP Auto Port
Aggregation Administrator’s Guide at
http://docs.hp.com -> I/O Cards and
Networking Software -> Auto Port
Aggregation (APA) for more information. A
standby LAN always uses two switches and thus
does not entail a SPOF.
• You cannot change the heartbeat configuration
while a cluster that uses CVM is running.