Installation guide

Fig u re 1.6 . Fen cin g a N o d e wit h Du al Fib re Ch an nel Co n n ect io ns
You can configure a node with one fencing method or multiple fencing methods. When you configure
a node for one fencing method, that is the only fencing method available for fencing that node. When
you configure a node for multiple fencing methods, the fencing methods are cascaded from one
fencing method to another according to the order of the fencing methods specified in the cluster
configuration file. If a node fails, it is fenced using the first fencing method specified in the cluster
configuration file for that node. If the first fencing method is not successful, the next fencing method
specified for that node is used. If none of the fencing methods is successful, then fencing starts again
with the first fencing method specified, and continues looping through the fencing methods in the
order specified in the cluster configuration file until the node has been fenced.
1.3.4 . Clust er Configurat ion Syst em
The Cluster Configuration System (CCS) manages the cluster configuration and provides
configuration information to other cluster components in a Red Hat cluster. CCS runs in each cluster
node and makes sure that the cluster configuration file in each cluster node is up to date. For
example, if a cluster system administrator updates the configuration file in Node A, CCS propagates
the update from Node A to the other nodes in the cluster (refer to Figure 1.7, “ CCS Overview” ).
Red Hat Ent erprise Linux 5 Clust er Suit e Overview
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