About setting up I/O fencing

Figure: Workflow to configure I/O fencing illustrates the tasks involved to configure I/O fencing.

Figure: Workflow to configure I/O fencing

Workflow to configure I/O fencing

See Preparing to configure I/O fencing.

See Setting up I/O fencing.

I/O fencing requires the coordinator disks be configured in a disk group. The coordinator disks must be accessible to each node in the cluster. These disks enable the vxfen driver to resolve potential split-brain conditions and prevent data corruption.

Review the following requirements for coordinator disks:

The I/O fencing configuration files include:


You must create this file to include the coordinator disk group information.


You must set the I/O fencing mode to SCSI-3.

You must configure the vxfen module to use DMP devices or iSCSI devices, and set the SCSI-3 disk policy as dmp.


When you run the vxfen startup file to start I/O fencing, the script creates this /etc/vxfentab file on each node with a list of all paths to each coordinator disk. The startup script uses the contents of the /etc/vxfendg and /etc/vxfenmode files.

Thus any time a system is rebooted, the fencing driver reinitializes the vxfentab file with the current list of all paths to the coordinator disks.


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

An example of the /etc/vxfentab file on one node resembles as follows:


In some cases you must remove disks from or add disks to an existing coordinator disk group.


If you remove disks from an existing coordinator disk group, then be sure to remove the registration and reservation keys from these disks before you add the disks to another disk group.