Enabling or disabling the preferred fencing policy

You can enable or disable the preferred fencing feature for your I/O fencing configuration.

You can enable preferred fencing to use system-based race policy or group-based race policy. If you disable preferred fencing, the I/O fencing configuration uses the default count-based race policy.

See About preferred fencing.

See How preferred fencing works.

To enable preferred fencing for the I/O fencing configuration

  1. Make sure that the cluster is running with I/O fencing set up.
    # vxfenadm -d
  2. Make sure that the cluster-level attribute UseFence has the value set to SCSI3.
    # haclus -value UseFence
  3. To enable system-based race policy, perform the following steps:

    • Make the Veritas Cluster Server (VCS) configuration writable.

      # haconf -makerw
    • Set the value of the cluster-level attribute PreferredFencingPolicy as System.

      # haclus -modify PreferredFencingPolicy System
    • Set the value of the system-level attribute FencingWeight for each node in the cluster.

      For example, in a two-node cluster, where you want to assign sys1 five times more weight compared to sys2, run the following commands:

      # hasys -modify sys1 FencingWeight 50
      # hasys -modify sys2 FencingWeight 10
    • Save the VCS configuration.

      # haconf -dump -makero
  4. To enable group-based race policy, perform the following steps:

    • Make the VCS configuration writable.

      # haconf -makerw
    • Set the value of the cluster-level attribute PreferredFencingPolicy as Group.

      # haclus -modify PreferredFencingPolicy Group
    • Set the value of the group-level attribute Priority for each service group.

      For example, run the following command:

      # hagrp -modify service_group Priority 1

      Make sure that you assign a parent service group an equal or lower priority than its child service group. In case the parent and the child service groups are hosted in different subclusters, then the subcluster that hosts the child service group gets higher preference.

    • Save the VCS configuration.

      # haconf -dump -makero
  5. To view the fencing node weights that are currently set in the fencing driver, run the following command:
    # vxfenconfig -a

To disable preferred fencing for the I/O fencing configuration

  1. Make sure that the cluster is running with I/O fencing set up.
    # vxfenadm -d
  2. Make sure that the cluster-level attribute UseFence has the value set to SCSI3.
    # haclus -value UseFence
  3. To disable preferred fencing and use the default race policy, set the value of the cluster-level attribute PreferredFencingPolicy as Disabled.
    # haconf -makerw
    # haclus -modify PreferredFencingPolicy Disabled
    # haconf -dump -makero