Storage Foundation and High Availability 7.4.2 Configuration and Upgrade Guide - AIX

This file stores the start and stop environment variables for I/O fencing:

• VXFEN_START - Defines the startup behavior for the I/O fencing module after a system reboot. Valid values include:

  1 - Indicates that I/O fencing is enabled to start up.

  0 - Indicates that I/O fencing is disabled to start up.

• VXFEN_STOP - Defines the shutdown behavior for the I/O fencing module during a system shutdown. Valid values include:

  1 - Indicates that I/O fencing is enabled to shut down.

  0 - Indicates that I/O fencing is disabled to shut down.

This file contains the following parameters:

• vxfen_mode

  • scsi3 - For disk-based fencing.

  • customized - For server-based fencing.

  • disabled - To run the I/O fencing driver but not do any fencing operations.

  • majority - For fencing without the use of coordination points.

• vxfen_mechanism

  This parameter is applicable only for server-based fencing. Set the value as cps.

• scsi3_disk_policy

  • dmp - Configure the vxfen module to use DMP devices

    The disk policy is dmp by default. If you use iSCSI devices, you must set the disk policy as dmp.

  Note:

  You must use the same SCSI-3 disk policy on all the nodes.

• List of coordination points

  This list is required only for server-based fencing configuration.

  Coordination points in server-based fencing can include coordinator disks, CP servers, or both. If you use coordinator disks, you must create a coordinator disk group containing the individual coordinator disks.

  Refer to the sample file /etc/vxfen.d/vxfenmode_cps for more information on how to specify the coordination points and multiple IP addresses for each CP server.

• single_cp

  This parameter is applicable for server-based fencing which uses a single highly available CP server as its coordination point. Also applicable for when you use a coordinator disk group with single disk.

• autoseed_gab_timeout

  This parameter enables GAB automatic seeding of the cluster even when some cluster nodes are unavailable.

  This feature is applicable for I/O fencing in SCSI3 and customized mode.

  0 - Turns the GAB auto-seed feature on. Any value greater than 0 indicates the number of seconds that GAB must delay before it automatically seeds the cluster.

  -1 - Turns the GAB auto-seed feature off. This setting is the default.

• detect_false_pesb

  0 - Disables stale key detection.

  1 - Enables stale key detection to determine whether a preexisting split brain is a true condition or a false alarm.

  Default: 0

  Note:

  This parameter is considered only when vxfen_mode=customized.

For disk-based I/O fencing, the /etc/vxfentab file on each node contains a list of all paths to each coordinator disk along with its unique disk identifier. A space separates the path and the unique disk identifier. An example of the /etc/vxfentab file in a disk-based fencing configuration on one node resembles as follows:

• DMP disk:

  
  /dev/vx/rdmp/rhdisk75 HITACHI%5F1724-100%20%20FAStT%5FDISKS%5F6
  00A0B8000215A5D000006804E795D075
  /dev/vx/rdmp/rhdisk76 HITACHI%5F1724-100%20%20FAStT%5FDISKS%5F6
  00A0B8000215A5D000006814E795D076
  /dev/vx/rdmp/rhdisk77 HITACHI%5F1724-100%20%20FAStT%5FDISKS%5F6
  00A0B8000215A5D000006824E795D077