Serviceguard NFS Toolkit A.11.11.06, A.11.23.05 and A.11.31.05 Administrator's Guide

Figure 1-7 A Host Configured as Adoptive Node for Multiple Packages
When Node_A fails, Node_B becomes the server for Pkg_1. If Node_C fails, Node_B will become
the server for Pkg_2. Alternatively, you can set the package control option in the control script,
nfs.cntl, to prevent Node_B from adopting more than one package at a time. With the package
control option, Node_B may adopt the package of the first node that fails, but if the second node
fails, Node_B will not adopt its package. The package control option prevents a node from
becoming overloaded by adopting too many packages. If an adoptive node becomes overloaded,
it can fail.
Cascading Failover with Three Adoptive Nodes
A package may be configured with up to three adoptive nodes. Figure 1-8 shows this
configuration. If Node_A fails, Pkg_1 is adopted by Node_B. However, if Node_B is down,
Pkg_1 is adopted by Node_C, and if Node_C is down, Pkg_1 is adopted by Node_D. The adoptive
nodes are listed in the package configuration file, /etc/cmcluster/nfs/nfs.conf, in the
order in which they will be tried. Note that all four nodes must have access to the disks for the
Pkg_1 file systems.
Supported Configurations 19