Setting up non-SCSI-3 fencing in virtual environments manually

Last published : Sep 11, 2026
To manually set up I/O fencing in a non-SCSI-3 PR compliant setup
  1. Configure I/O fencing either in majority-based fencing mode with no coordination points or in server-based fencing mode only with CP servers as coordination points.
See Setting up server-based I/O fencing manually.
See Setting up majority-based I/O fencing manually.
  1. Make sure that the VCS cluster is online and check that the fencing mode is customized mode or majority mode.
    \# vxfenadm -d
    1. Make sure that the cluster attribute UseFence is set to SCSI-3.
    \# haclus -value UseFence
  2. On each node, edit the /etc/vxenviron file as follows:
    data_disk_fencing=off
    1. Enter the following command to change the vxfen_min_delay parameter value:
    \# chdev -l vxfen -P -a vxfen_vxfnd_tmt=25
  3. On each node, edit the /etc/vxfenmode file as follows:
    loser_exit_delay=55
    vxfen_script_timeout=25
    Refer to the sample /etc/vxfenmode file.
    1. On each node, set the value of the LLT sendhbcap timer parameter value as follows:
      • Run the following command:
    lltconfig -T sendhbcap:3000
  • Add the following line to the /etc/llttab file so that the changes remain persistent after any reboot:
    set-timer senhbcap:3000
    1. On any one node, edit the VCS configuration file as follows:
      • Make the VCS configuration file writable:
    \# haconf -makerw
  • For each resource of the type DiskGroup, set the value of the MonitorReservation attribute to 0 and the value of the Reservation attribute to NONE. \# hares -modify <dg_resource> MonitorReservation 0

    ```bash
        \# hares -modify \<dg_resource\> Reservation "NONE"
  • Run the following command to verify the value: \# hares -list Type=DiskGroup MonitorReservation!=0

    ```bash
    \# hares -list Type=DiskGroup Reservation!="NONE"
The command should not list any resources.
  • Modify the default value of the Reservation attribute at type-level.
    \# haattr -default DiskGroup Reservation "NONE"
    -  Make the VCS configuration file read-only
        \# haconf -dump -makero
  1. Make sure that the UseFence attribute in the VCS configuration file main.cf is set to SCSI-3.
  2. To make these VxFEN changes take effect, stop and restart VxFEN and the dependent modules
    • On each node, run the following command to stop VCS:
      \# /etc/init.d/vcs.rc stop
      • After VCS takes all services offline, run the following command to stop VxFEN:
      \# /etc/init.d/vxfen.rc stop
  • On each node, run the following commands to restart VxFEN and VCS:
\# /etc/init.d/vxfen.rc start
\# /etc/init.d/vcs.rc start