Installation guide
# cd /boo t
# mki nitrd -f -v initrd-kernel.i mg kernel
For example, the currently running kernel in the following m kinitrd command is 2.6.9-34.0.2.EL:
# mki nitrd -f -v initrd-2.6.9-34 .0.2.EL.img 2.6.9-34.0.2.EL
Note
You can determine the currently running kernel by running uname -r.
5. Restart the node.
2.5. Considerations for Using Quorum Disk
Quorum Disk is a disk-based quorum daemon, qdiskd, 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 qdiskd 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 qdiskd to meet those needs.
Note
Configuring qdiskd 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,
qdiskd is configured to provide enough quorum votes to maintain quorum even though only one
node is working.
Important
Overall, heuristics and other qdiskd parameters for your Red Hat Cluster depend on the site
environment and special requirements needed. T o understand the use of heuristics and other
qdiskd parameters, refer to the qdisk(5) man page. If you require assistance understanding and
using qdiskd for your site, contact an authorized Red Hat support representative.
If you need to use qdiskd, you should take into account the following considerations:
Cluster node vot es
Each cluster node should have the same number of votes.
CMAN membership timeout value
The CMAN membership timeout value (the time a node needs to be unresponsive before CMAN
considers that node to be dead, and not a member) should be at least two times that of the
qdiskd membership timeout value. The reason is because the quorum daemon must detect
Chapter 2. Before Configuring a Red Hat Cluster
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