Installation guide

<fence>

</fence>

</clusternode>

</clusternodes>

</fencedevices>

<rm>

</rm>

In this example, the fourth line of the configuration (annotated as " INVALID " here) contains an

invalid value for the XML attribute, no d ei d in the cl usternod e line for no d e-

0 1. example. co m. The value is a negative value ("-1") instead of a positive value ("1"). For the

no d ei d attribute, the value must be a positive value.

2.8. Considerat ions for Net workManager

The use of Net wo rkMan ag er is not supported on cluster nodes. If you have installed

Net wo rkMan ag er on your cluster nodes, you should either remove it or disable it.

Note

The cman service will not start if NetworkManager is either running or has been configured to

run with the chkconfi g command.

2.9. Considerat ions for Using Quorum Disk

Quorum Disk is a disk-based quorum daemon, q d i skd , that provides supplemental heuristics to

determine node fitness. With heuristics you can determine factors that are important to the operation

of the node in the event of a network partition. For example, in a four-node cluster with a 3:1 split,

ordinarily, the three nodes automatically " win" because of the three-to-one majority. Under those

circumstances, the one node is fenced. With q d i skd however, you can set up heuristics that allow

the one node to win based on access to a critical resource (for example, a critical network path). If

your cluster requires additional methods of determining node health, then you should configure

q d i skd to meet those needs.

Note

Configuring q d i skd is not required unless you have special requirements for node health. An

example of a special requirement is an "all-but-one" configuration. In an all-but-one

configuration, q d i skd is configured to provide enough quorum votes to maintain quorum

even though only one node is working.

Red Hat Ent erprise Linux 6 Clust er Administ rat ion