How to check whether IO fencing is on with Veritas VCS ?

Product

 

EMC Symmetrix VMAX  Series

 

Description

 

How to check whether IO fencing is on with Veritas VCS ?

 

Fix


1) Check the gabconfig -a command output. Watch for an entry on 'Port b'.

->/sbin/gabconfig -a
GAB Port Memberships
===============================================================
Port a gen   55b901 membership 01
Port b gen   55b908 membership 01   ==> IO fencing is used.
Port h gen   55b931 membership 01   ==> had daemon is running, understand the cluster is up & running

Here a short help on how to interpret the gabconfig -a output:
Missing 'Port a' entry: 'gab' is not running: you are missing a basic cluster component.
Missing 'Port b' entry: 'vxfen' not running on this server. It usually is automatically started at boot time however you can manually start it up with next command: '/etc/init.d/vxfen start'
Missing 'Port h' entry: 'had' daemon is not running on the local server (meaning it's not registered into the cluster). You can have it started by running command: hastart

2) Check the coordinator disk group has correctly been set-up and cluster node members have correctly registered.

Watch for the content of file '/etc/vxfentab'. This file is automatically created at IO fencing set-up time (when it is used) and contains the list of devices  included into the coordinator disk group. According to the Veritas recommendations, you should have 3 devices in this disk group. Please note that 'emcpower' pseudo devices are allowed.

Here 2 examples of a correct '/etc/vxfentab' file

1st example: 3 different devices, dual pathed, no PowerPath pseudo devices used:
->cat /etc/vxfentab
/dev/rdsk/c4t8d30s2
/dev/rdsk/c5t9d30s2
/dev/rdsk/c4t8d31s2
/dev/rdsk/c5t9d31s2
/dev/rdsk/c4t8d32s2
/dev/rdsk/c5t9d32s2

2nd example: 3 different powerpath pseudo devices used (refer to 'powermt display' to determine the number of subpaths:
->cat /etc/vxfentab
/dev/rdsk/emcpower5c
/dev/rdsk/emcpower6c
/dev/rdsk/emcpower7c

Run command: vxfenadm -g all -f /etc/vxfentab to display the registration keys. In the example below, IO fencing is used. Please check that all cluster node members in the cluster have registered on all paths.

Here an example of a correct output:

->/sbin/vxfenadm -g all -f /etc/vxfentab

Device Name: /dev/rdsk/c4t8d30s2
Total Number Of Keys: 2
key[0]:
        Key Value [Numeric Format]:  66,45,45,45,45,45,45,45
        Key Value [Character Format]: B-------
key[1]:
        Key Value [Numeric Format]:  65,45,45,45,45,45,45,45
        Key Value [Character Format]: A-------

Device Name: /dev/rdsk/c5t9d31s2
Total Number Of Keys: 2
key[0]:
        Key Value [Numeric Format]:  66,45,45,45,45,45,45,45
        Key Value [Character Format]: B-------
key[1]:
        Key Value [Numeric Format]:  65,45,45,45,45,45,45,45
        Key Value [Character Format]: A-------

Device Name: /dev/rdsk/c4t8d32s2
Total Number Of Keys: 2
key[0]:
        Key Value [Numeric Format]:  66,45,45,45,45,45,45,45
        Key Value [Character Format]: B-------
key[1]:
        Key Value [Numeric Format]:  65,45,45,45,45,45,45,45
        Key Value [Character Format]: A-------

Device Name: /dev/rdsk/c5t9d32s2
Total Number Of Keys: 2
key[0]:
        Key Value [Numeric Format]:  66,45,45,45,45,45,45,45
        Key Value [Character Format]: B-------
key[1]:
        Key Value [Numeric Format]:  65,45,45,45,45,45,45,45
        Key Value [Character Format]: A-------

Device Name: /dev/rdsk/c5t9d30s2
Total Number Of Keys: 2
key[0]:
        Key Value [Numeric Format]:  66,45,45,45,45,45,45,45
        Key Value [Character Format]: B-------
key[1]:
        Key Value [Numeric Format]:  65,45,45,45,45,45,45,45
        Key Value [Character Format]: A-------

Device Name: /dev/rdsk/c4t8d31s2
Total Number Of Keys: 2
key[0]:
        Key Value [Numeric Format]:  66,45,45,45,45,45,45,45
        Key Value [Character Format]: B-------
key[1]:
        Key Value [Numeric Format]:  65,45,45,45,45,45,45,45
        Key Value [Character Format]: A-------

3) Check for the cluster-wide system state by running vxfenadm -d. In the example below IO fencing is used, hence you should see all cluster member nodes in running mode.

->/sbin/vxfenadm -d

I/O Fencing Cluster Information:
================================

Cluster Members:
        * 0 (sunv880tsa)
          1 (sunv880tsb)

RFSM State Information:
        node   0 in state  8 (running)
        node   1 in state  8 (running)

 

For more information, Refer to EMC Knowledgebase article 8942