Checking shared disks for I/O fencing

Make sure that the shared storage you set up while preparing to configure VCS meets the I/O fencing requirements. You can test the shared disks using the vxfentsthdw utility. The two nodes must have ssh (default) or rsh communication. To confirm whether a disk (or LUN) supports SCSI-3 persistent reservations, two nodes must simultaneously have access to the same disks. Because a shared disk is likely to have a different name on each node, check the serial number to verify the identity of the disk. Use the vxfenadm command with the -i option. This command option verifies that the same serial number for the LUN is returned on all paths to the LUN.

Make sure to test the disks that serve as coordinator disks.

You can use the vxfentsthdw utility to test disks either in DMP format or in raw format.

DMP opens the secondary (passive) paths with an exclusive flag in Active/Passive arrays. So, if you test the secondary (passive) raw paths of the disk, the vxfentsthdw command may fail due to DMP's exclusive flag.

The vxfentsthdw utility has additional options suitable for testing many disks. Review the options for testing the disk groups (-g) and the disks that are listed in a file (-f). You can also test disks without destroying data using the -r option.

See the Cluster Server Administrator's Guide.

Checking that disks support SCSI-3 involves the following tasks:

See Verifying Array Support Library (ASL).

See Verifying that the nodes have access to the same disk.

See Testing the disks using vxfentsthdw utility.