Serviceguard NFS Toolkit A.11.31.02, A.11.11.06, and A.11.23.05 Administrator's Guide

Figure 1-3 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 1-4 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.
16 Overview of Serviceguard NFS