About I/O fencing configuration files

Table: I/O fencing configuration files lists the I/O fencing configuration files.

Table: I/O fencing configuration files

File

Description

/etc/default/vxfen

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.

The installer sets the value of these variables to 1 at the end of VCS configuration.

If you manually configured VCS, you must make sure to set the values of these environment variables to 1.

/etc/vxfendg

This file includes the coordinator disk group information.

This file is not applicable for server-based fencing.

/etc/vxfenmode

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.

  • 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.

    • raw - Configure the vxfen module to use the underlying raw character devices

    Note:

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

  • security

    This parameter is applicable only for server-based fencing.

    1 - Indicates that communication with the CP server is in secure mode. This setting is the default.

    0 - Indicates that communication with the CP server is in non-secure mode.

  • 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 requires that I/O fencing is enabled.

    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.

/etc/vxfentab

When I/O fencing starts, the vxfen startup script creates this /etc/vxfentab file on each node. The startup script uses the contents of the /etc/vxfendg and /etc/vxfenmode files. Any time a system is rebooted, the fencing driver reinitializes the vxfentab file with the current list of all the coordinator points.

Note:

The /etc/vxfentab file is a generated file; do not modify this file.

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:

  • Raw disk:

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

For server-based fencing, the /etc/vxfentab file also includes the security settings information.

For server-based fencing with single CP server, the /etc/vxfentab file also includes the single_cp settings information.