Managing Serviceguard NFS for Linux, March 2009

The cmmodpkg command in the background allows the control script to complete and finish
bringing up the package. There is a small window of time, during which if one package has
begun to fail over but the cmmodpkg command has not executed, the other package can fail over
and the host will adopt it. In other words, if two packages fail over at approximately the same
time, a host may adopt both packages, even though the package control option is specified. If
the cmmodpkg -d command is omitted from the NFS control script the host sage can adopt both
pkg01 and pkg02, if their primary nodes fail.
NOTE: The above changes in the external script must be done only in the adoptive node and
not on the external script in the primary node. If there are more than 2 packages the user may
repeat the cmmodpkg command as many times required with other package names. Consider
making FAILBACK_POLICY as AUTOMATIC to free the adoptive node as early as possible so that
adoptive node is ready to accept pkg02 in case it fails.
Configuring Multiple Adoptive Nodes for Cascading Failover
This configuration has two packages and three servers. One server is the primary node for both
packages. The other servers are adoptive nodes for the two packages. Figure 3-5 illustrates this
configuration. Dotted lines indicate which servers are adoptive nodes for the packages. Figure 3-6
illustrates the configuration after host thyme fails.
Figure 3-5 Cascading Failover with Three Servers
Figure 3-6 shows the cascading failover configuration after host thyme has failed. Host basil
is the first adoptive node configured for pkg01, and host sage is the first adoptive node
configured for pkg02.
48 Sample Configurations