Installation guide

</fencedevices>
<rm>
</rm>
</cluster>
Examp le 7.2. cl uster.co nf Sample: Basic T wo - N o d e Co n f ig u rat io n
<cluster name="mycluster" config_version="2">
<cman two_node="1" expected_votes="1"/>
<clusternodes>
<clusternode name="node-01.example.com" nodeid="1">
<fence>
</fence>
</clusternode>
<clusternode name="node-02.example.com" nodeid="2">
<fence>
</fence>
</clusternode>
</clusternodes>
<fencedevices>
</fencedevices>
<rm>
</rm>
</cluster>
The co nsensus Value for totem in a Two-Node Cluster
When you create a two-node cluster and you do not intend to add additional nodes to the cluster at a
later time, then you should omit the co nsensus value in the to tem tag in the cluster. co nf file so
that the co nsensus value is calculated automatically. When the co nsensus value is calculated
automatically, the following rules are used:
If there are two nodes or fewer, the co nsensus value will be (token * 0.2), with a ceiling of 2000
msec and a floor of 200 msec.
If there are three or more nodes, the co nsensus value will be (token + 2000 msec)
If you let the cman utility configure your consensus timeout in this fashion, then moving at a later time
from two to three (or more) nodes will require a cluster restart, since the consensus timeout will need
to change to the larger value based on the token timeout.
If you are configuring a two-node cluster and intend to upgrade in the future to more than two nodes,
you can override the consensus timeout so that a cluster restart is not required when moving from
two to three (or more) nodes. This can be done in the cl uster.co nf as follows:
<totem token="X" consensus="X + 2000" />
Note that the configuration parser does not calculate X + 2000 automatically. An integer value must
be used rather than an equation.
Red Hat Ent erprise Linux 6 Clust er Administ rat ion
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