Managing Serviceguard Sixteenth Edition, March 2009

What You Must Keep in Mind
The following restrictions apply:
• You must not change the configuration of all heartbeats at one time, or change or
delete the only configured heartbeat.
At least one working heartbeat, preferably with a standby, must remain unchanged.
• In a CVM configuration, you can add and delete only data LANs and IP addresses.
You cannot change the heartbeat configuration while a cluster that uses CVM is
running.
• You cannot add interfaces or modify their characteristics unless those interfaces,
and all other interfaces in the cluster configuration, are healthy.
There must be no bad NICs or non-functional or locally switched subnets in the
configuration, unless you are deleting those components in the same operation.
• You cannot change the designation of an existing interface from HEARTBEAT_IP
to STATIONARY_IP, or vice versa, without also making the same change to all peer
network interfaces on the same subnet on all other nodes in the cluster.
Similarly, you cannot change an interface from IPv4 to IPv6 without also making
the same change to all peer network interfaces on the same subnet on all other
nodes in the cluster
• You cannot change the designation of an interface from STATIONARY_IP to
HEARTBEAT_IP unless the subnet is common to all nodes.
Remember that the HEARTBEAT_IP must on the same subnet on all nodes, except
in cross-subnet configurations; see “Cross-Subnet Configurations” (page 41).
• You cannot delete a primary interface without also deleting any standby interfaces,
unless the standby is being used by another primary interface that is not being
deleted.
• You cannot delete a subnet or IP address from a node while a package that uses
it (as a monitored_subnet, ip_subnet, or ip_address) is configured to run on that node.
See the package networking parameter descriptions (page 270) for more information.
• You cannot change the IP configuration of an interface (NIC) used by the cluster
in a single transaction (cmapplyconf).
You must first delete the NIC from the cluster configuration, then reconfigure the
NIC (using ifconfig (1m), for example), then add the NIC back into the cluster.
332 Cluster and Package Maintenance