Question about reconfiguring a Serviceguard cluster...

[SDVICK]

Hello all,

I believe I already know the answer but I wanted to verify before performing the steps.

I'm running MC/SG 11.13 and we recently migrated the package aware volume group from one EMC to another. I need to update the cluster lock PV and VG but when I attempted it before I couldn't get the configuration to apply because of errors w/ the PV/VG not being cluster aware (after I did the vgchange -c n VG).

I went back and re-read the SG manual and it doesn't mention the steps to follow when changing the PV/VG of the cluster, just that the cluster has to be down to execute. After poking around the forums, I never found a clear cut answer. However, I found a few posts that were not w/ the same issue but talked about reconfiguring the cluster.

I'm assuming that after bringing the cluster down and reverting the VG configuration to not be cluster aware, I need to delete the current cluster config (via cmdeleteconf), check the config (cmcheckconf) and then apply the new configuration for the cluster and the package (cmapplyconf -k -C CLUSTER.ascii -P PACKAGE.ascii).

Is there anything I'm missing?

Thanx in advance. (Points will be submitted for all answers. )

[Steven E. Protter]

Shalom,

Note that your SG version is very much out of date.

If the cluster is functioning, you should be able to change the cluster lock disk without bringing down the cluster. The new disk must be on shared storage and visible to both nodes on the cluster.

After making the change to the lock disk, you should be able to use cmcheckconf and then cmapplyconf

I don't think you are missing anything, but I would go back and check that the new lock disk is visible to all cluster nodes.

Being able to do this without downing the cluster is based on my experience with SG which ranges from 11.14 to 11.19 versions.

In general, making the VG configuration not cluster aware, means activating it at boot, which would make it not workable as a cluster lock disk.

SEP

[melvyn burnard]

>I need to delete the current cluster config (via cmdeleteconf)
No, not necessarily
The main thing to do is make sure the cluster lock VG (an dpreferably all of the cluster VG's) are listed in the cluster ascii file.
Then do the cmcheckconf/cmapplyconf
Having the VG's listed in the ascii file tells the cmapplyconf to mark them as cluster aware, bit for the cluster lock VG, you also need to make sure it is activated on the node where you run the cmapplyconf from.

You should also be aware you ar erunning a very old, and now unsupported, version iof Serviceguard

[SDVICK]

Thanx Steven and Melvyn for the replies.

I know that this version is very old. It is a legacy system that I inherited and, because it's going away in the next 6 months, it's not feasible to upgrade.

In any case, version 11.13 will not allow the update while the cluster is running. The output from the apply command while the cluster is running:

Error: Modifying FIRST_CLUSTER_LOCK_VG value from /dev/~ to /dev/~ while cluster CLUSTER is running is not supported.
FIRST_CLUSTER_LOCK_PV value for node NODE cannot be modified from /dev/dsk/c~ to /dev/dsk/c~ while cluster is running.
(note, I've removed identifying info).

If I take down the cluster and try to apply the new config, it complains that it can't read the lock VG (because it has been deactivated when the package was brought down) and I can't activate the VG with the cluster down and if I remove the cluster aware settings on the VG and activate it, the apply command complains that the VG is not cluster aware.

I think that I basically have to re-create the configuration, much like I would if I were changing the name of the cluster.

[melvyn burnard]

This version of Serviceguard basically allows for very little to be done on-line.