Removing a quorum disk

[Ziggy Filek]

I have a cluster that somebody configured to stay up with only one node. The configuration is as follows: 3 nodes with 1 vote each and a Quorum disk with 3 votes. Expected votes is 6, quorum is 4. I need to remove this quorum disk leaving a standard configuration with 3 nodes 1 vote each, quorum 2. I will be in a position to reboot the entire cluster for this.
I'd like to do this without using CLUSTER_CONFIG. I intend to modify the following parameters in MODPARAMS.DAT on all 3 nodes to be:
DISK_QUORUM=""
EXPECTED_VOTES = 3
and then run AUTOGEN GETDATA SETPARAMS
and re-boot the entire cluster.
Is this going to work?
What do I do with the QDSKVOTES parameter? Set it to zero? Or ignore it, since DISK_QUORUM will be the null string?
I'd appreciate any insight on this.
Also, what should I do if the cluster refuses to boot? Reset these parameters from console to their old values?
Thanks again. Z.

[Jan van den Ende · Accepted solution]

Ziggy,

That as the exact procedure.

Just be sure NOT to reboot any of the systems before the others are down.

Be prepared to expect the first node of your new cluster to hang until the second has also reached the "Waiting to form or join a cluster"

This procedure is much more straightforward as removing a quorum disk from a running cluster, so if you can, take the easy road of a cluster reboot.

success.

Proost.

Have one on me.

jpe

[Ziggy Filek]

What about the QDSKVOTES parameter? Set to zero?
Thanks again!

[Jan van den Ende]

Ziggy,

as long as DISK_QUORUM is "", QDSKVOTES is irrelevant.
But for future clarity, it is neater to set it to 0 (zero).

Proost.

Have one on me.

jpe

[Volker Halle]

Ziggy,

once you've run AUTOGEN, make sure to re-check the parameters on disk (MC SYSGEN> USE CURRENT) to make real sure, that they are as expected.

You can reboot the whole cluster in one attempt, if you shutdown all nodes with specifying CLUSTER_SHUTDOWN (if you're running V7.2 or higher).

Volker.

[comarow]

While the religious answer is to execute autogen, there's really no reason. These parameters really don't effect other parameters.

Just use current
set the parameters
disk_quorum = ""
expected_votes =3
write current

That said, make sure it is also set in modparams.dat so that when someone executes autogen they won't destroy your system.

Watch out for the many duplicate values in modparams.dat, as every update will create another set of your cluster parameters. This would be a good time to clean out all the duplicate parameters.

You will forever need two nodes to stay up, unless you do an interactive boot. You can adjust quorum at the IPC prompt or with the availability manager should the need arise.

There's no reason it shouldn't boot. If it doesn't it means there's a mistake, so you would handle it like any interactive boot problem.

Have fun.

[Peter Zeiszler]

Make sure to archive your older modparams.dat file to another name for historical reference. That way if someone accidently cleans up the newest version and performs autogen it doesn't destroy the cleanup you have done. (talking from experience with other parameters mysteriously recovering onto a system by people "helping" me)

[Ziggy Filek]

Thank you everybody. I was able to successfully perform this task. Ziggy.