3 Replies Latest reply: Apr 23, 2012 10:48 PM by hitgon RSS

    Voting disks

    925175
      Hi,

      How is it possible that the nodes in RAC cluster will see only some of the voting disks in the cluster?
      I ask because I came across the subject on Oracle docs: http://docs.oracle.com/cd/E11882_01/rac.112/e17264/adminoc.htm#TDPRC570

      If this sutuation is possible, is it normal? how will it affect my cluster?

      Regards,
      Igor.
        • 1. Re: Voting disks
          hitgon
          Hi,

          at least three or odd number of the voting disks is required by all the available nodes in the clusters.

          In RAC, CSSD processes (Cluster Services Synchronization Daemon) monitor the health of RAC nodes employing two distinct heart beats: Network heart beat and Disk heart beat. Healthy nodes will have continuous network and disk heartbeats exchanged between the nodes. Break in heart beat indicates a possible error scenario. There are few different scenarios possible with missing heart beats:
          1. Network heart beat is successful, but disk heart beat is missed.
          2. Disk heart beat is successful, but network heart beat is missed.
          3. Both heart beats failed.

          Regards
          Hitgon
          • 2. Re: Voting disks
            925175
            Thanks Hitgon, helpful response but it doesn't really answers my question :)

            My questions were:
            1. Can some nodes in a cluster not access all the voting disks in the cluster?
            2. If the situation above is possible, is it normal and how it affects the cluster?
            3. (new question) Does the command "crsctl query css votedisk" outputs the voting disks that the current node can access, or is the command outputs a global information?

            Regards,
            Igor.

            Edited by: 922172 on Apr 23, 2012 6:05 AM
            • 3. Re: Voting disks
              hitgon
              Hello Igor

              1. Can some nodes in a cluster not access all the voting disks in the cluster?

              No....
              nodes in a cluster must required the access of at least old numbers of voting disk either 1 or 3 etc...

              without the access of voting disk to nodes become un-healthy means network and disk heart beat is failed in this case that node will reboot.

              2. If the situation above is possible, is it normal and how it affects the cluster?
              Not possible....
              It's not a normal situation

              purpose of Voting disk is used for communicate the network and disk heat beats between the cluster nodes so without the access of voting disk how cluster remain healthy so that nodes must need at least
              odd numbers of voting disk.

              3. (new question) Does the command "crsctl query css votedisk" outputs the voting disks that the current node can access, or is the command outputs a global information?

              Use the crsctl query css votedisk command to display the voting disks used by Cluster Synchronization Services, the status of the voting disks, and the location of the disks, whether they are stored on Oracle ASM or elsewhere.

              Regards
              Hitgon

              Edited by: hitgon on Apr 23, 2012 8:47 PM