Managing Serviceguard Sixteenth Edition, March 2009

Table 7-1 Types of Changes to the Cluster Configuration (continued)
Required Cluster StateChange to the Cluster Configuration
Must delete the interface from the cluster configuration,
reconfigure it, then add it back into the cluster
configuration. See “What You Must Keep in Mind”
(page 332). Cluster can be running throughout.
Reconfigure IP addresses for a NIC used by the
cluster
Cluster can be running.Change NETWORK_FAILURE_DETECTION
parameter (see “Monitoring LAN Interfaces
and Detecting Failure: Link Level” (page 93))
Cluster can be running.Change NETWORK_AUTO_FAILBACK
parameter
Cluster can be running.Change NETWORK_POLLING_INTERVAL
Cluster can be running. See the entries for these
parameters under “Cluster Configuration Parameters
” (page 138) for more information.
Change IP Monitor parameters: SUBNET,
IP_MONITOR, POLLING TARGET
Cluster can be running, except in CVM environment;
see the NOTE below this table.
Change MEMBER_TIMEOUT and
AUTO_START_TIMEOUT
Cluster and package can be running.Change Access Control Policy
Cluster can be running.
A change that would cause a running package to fail
will trigger a warning, giving you a chance to cancel
(unless you use cmapplyconf -f).
Change capacity and weight parameters.
NOTE: If you are using CVM or CFS, you cannot change MEMBER_TIMEOUT or
AUTO_START_TIMEOUT while the cluster is running. This is because they affect the
aggregate failover time, which is only reported to the CVM stack on cluster startup.
You also cannot change the quorum configuration while SG-CFS-pkg is running.
Previewing the Effect of Cluster Changes
Many variables affect package placement, including the availability of cluster nodes;
the availability of networks and other resources on those nodes; failover and failback
policies; and package weights, dependencies, and priorities, if you have configured
them. You can preview the effect on packages of certain actions or events before they
actually occur.
For example, you might want to check to see if the packages are placed as you expect
when the cluster first comes up; or preview what happens to the packages running on
a given node if the node halts, or if the node is then restarted; or you might want to
see the effect on other packages if another, currently disabled, package is enabled, or
if a package halts and cannot restart because none of the nodes on its node_list is
available.
324 Cluster and Package Maintenance