Why does fencing fail when using fencing delays in RHEL?

Environment

• Red Hat Enterprise Linux (RHEL) 5 or 6 with the High Availability Add On

Issue

• When using fence delays to prevent split brain scenarios, the fencing operation fails.

Resolution

RHEL5
Update to cman-2.0.115-96.el5_8.3 or later.

RHEL6
Update fence-agents-3.1.5-17.el6 or later.

Root Cause

When the delay option is passed to the fencing script, the fencing script will login to the fence device. After the fencing script has logged into the fencing device it will sleep for X seconds where X is the fencedevice delay value. After the X seconds, the fencing script will try to run a command on the fencing device and the command will fail because the fencing device has already closed the idle connection by then because the session was idle for to long.

Then issue likely affects a range of fencing scripts.

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