Symantec Veritas Cluster Server One, Installation Manual

Page: 154 / 210

154 Troubleshooting
Troubleshooting I/O fencing
Resolving an actual potential split brain condition
An actual split brain condition is where two systems are up, but there is no
heartbeat between them. In the following example, system 1 and system 2 are
both up, but there is no heartbeat between them. Then, system 2 is up and
system 1 is ejected.
To resolve an actual potential split brain condition
1 Determine if system 1 is up.
2 If it is up and running, shut it down and repair the private network links to
remove the split brain condition.
3 Reboot system 1.
Resolving an apparent potential split brain condition
An apparent split brain condition is where one system is up and one system is
down, and there is no heartbeat between them. In the following example, system
2 is down, and system 1 is ejected and there is no heartbeat between the two
systems.
To resolve an apparent potential split brain condition
1 Physically verify that system 2 is down.
2 Log in to system 1 and check to see that I/O fencing is not configured. Enter
the following:
vxfenadm -d
The command output shows that I/O fencing is not configured on system 1.
3 Verify that the systems are registered with the coordinator disks. Enter the
following:
vxfenadm -g all -f /etc/vxfentab
The command output identifies the keys registered with the coordinator
disks.
4 Clear the keys on the coordinator disks as well as the data disks using the
command
/opt/VRTSvcs/vxfen/bin/vxfenclearpre
.
See “ Using the vxfenclearpre command to clear keys after split brain ” on
page 155.
5 Make any necessary repairs to system 2 and reboot.