How can I check which cluster node is the master of the quorum disk on Red Hat Enterprise Linux 5?

Solution Verified - Updated

Environment

  • Red Hat Enterprise Linux Server 5 (with the High Availabilty or Resilient Storage Add Ons)

Red Hat Enterprise Linux 6 can be found here: How can I check which cluster node is the master of the quorum disk on Red Hat Enterprise Linux 6?

Issue

  • I want to check periodically the status of the Quorum Disk Roles.
  • How can I check the Master Role of the quorum disk?
  • How to know which node has the qdisk master role in RHEL5 cluster?

Resolution

There are various approaches to determining the quorum disk master. The following are listed in order of decreasing ease of use:

  • The mkqdisk command, in debug mode, will read the information written in the quorum device. That includes telling who is the master.

      # mkqdisk -dL
  mkqdisk v0.6.0
  [...]
          Label:                qdisk
  [...]
  Status block for node 1
          Last updated by node 1
          Last updated on Tue Jan 26 10:26:50 2010
          State: Master
  [...]
  Status block for node 2
          Last updated by node 2
          Last updated on Tue Jan 26 10:23:27 2010
          State: Running

  • In a master_wins quorum disk configuration, check the output of cman_tool status. The quorum disk daemon, qdiskd will only report its vote on the master node. (This approach does not apply to non-master_wins configurations.)

      # cman_tool status |grep votes

    • example from the master node:

        # cman_tool status |grep votes
  Expected votes: 3
  Quorum device votes: 1 <----
  Total votes: 3
  Node votes: 1

    • example from the non-master node:

        # cman_tool status |grep votes
  Expected votes: 3
  Total votes: 2
  Node votes: 1

  • Quorum disk roles are written to /var/log/messages file every time a change occurs in quorum disk membership. Check /var/log/messages:

      # grep qdisk.*master /var/log/messages*

    • example from the master node:

        qdiskd[1920]: <info> Assuming master role

    • example from a non-master node:

        qdiskd[1918]: <info> Node 1 is the master

  • Refer to the following to capture additional logging information from the qdiskd daemon.

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