Administrators can use the
vxfenadm command to troubleshoot and test fencing configurations.
The command's options for use by administrators are as follows:
Refer to the
vxfenadm(1m) manual page for a complete list of the command options.
The key defined by VxVM associated with a disk group consists of seven bytes maximum. This key becomes unique among the systems when the VxVM prefixes it with the ID of the system. The key used for I/O fencing, therefore, consists of eight bytes.
Click the thumbnail above to view full-sized image.
The keys currently assigned to disks can be displayed by using the
For example, from the system with node ID 1, display the key for the disk /dev/rhdisk74 by entering:
vxfenadm -g /dev/rhdisk74
Reading SCSI Registration Keys...
Device Name: /dev/
Total Number of Keys: 1
Key Value [Numeric Format]: 65,45,45,45,45,45,45,45
Key Value [Character Format]: A-------
The -g option of
vxfenadm displays all eight bytes of a key value in two formats. In the numeric format, the first byte, representing the Node ID, contains the system ID 65. The remaining bytes contain the ASCII values of the letters of the key, in this case, "-------." In the next line, the node ID 0 is expressed as "A;" node ID 1 would be "B."
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 to verify that the same serial number for the LUN is returned on all paths to the LUN.
For example, an EMC disk is accessible by the /dev/rhdisk75 path on node A and the /dev/rhdisk76 path on node B.
To verify that the nodes see the same disks
vxfenadm -i /dev/rhdisk75
Vendor id : EMC
Product id : SYMMETRIX
Revision : 5567
Serial Number : 42031000a
The same serial number information should appear when you enter the equivalent command on node B using the/dev/rhdisk76 path.
On a disk from another manufacturer, Hitachi Data Systems, the output is different and may resemble:
vxfenadm -i /dev/rhdisk77
Vendor id : HITACHI
Product id : OPEN-3
Revision : 0117
Serial Number : 0401EB6F0002
Refer to the
vxfenadm(1M) manual page.