Cluster vglock Unavailable

 
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chindi
Respected Contributor

Cluster vglock Unavailable

We have MC service guard A.11.17.00 in our environment  to which we have vglock from EVA4K .

We need to decommision EVA4K , we havea migrated rest of our packages on other storage but only vglock is pending.

Its 1 gb lun , not mounted "vg" .

 

The question is if we just decommision EVA4K will my running cluster be affected ?

What if vg_lock pv status in unvailable ??

 

6 REPLIES 6
Bill Hassell
Honored Contributor

Re: Cluster vglock Unavailable

 If the lock disk is not available, the cluster will fail to start.

 

The VG lock volume group contains at least one disk which is the cluster lock disk. This can be a very small disk (10 MB for example), but must exist in order for the cluster to form. It can be a separate VG but more typically, it can be part of a package VG. Since only a small part of the disk is used in the LVM headers, it can be a disk within the package.



Bill Hassell, sysadmin
chindi
Respected Contributor

Re: Cluster vglock Unavailable

Hi Bill ,

 

But nothing will happen to running cluster right ?

Its a separate vg of 1gb .

Bill Hassell
Honored Contributor

Re: Cluster vglock Unavailable

The lock disk is checked regularly, and if it is removed, you'll get a message in syslog.log something like this:

Unable to obtain Cluster Lock. Operation has time out.
WARNING: Cluster lock disk /dev/dsk/c1t2d0 has failed.
Until it is fixed, a single failure could cause all nodes in the cluster to crash.

So the running cluster will be put into an unprotected state. Any failure within the cluster will likely crash every node. The cluster will likely be able to shutdown and restart but with lots of error messages in syslog.log.



Bill Hassell, sysadmin
chindi
Respected Contributor

Re: Cluster vglock Unavailable

Hi Bill,

 

Any failure in running cluster means what kind of failures ?

Also if i need to crete a new vg , what is the process for the same ??

Bill Hassell
Honored Contributor
Solution

Re: Cluster vglock Unavailable

>> Any failure in running cluster means what kind of failures ?

 

Any failure detected by the cluster or package. Such things as a missing heartbeat over the network, a problem with the package services or package monitor scripts, a hardware failure on one of the nodes, etc. In other words, the types of failures that Service Guard is designed to circumvent. The cluster will be unable to switch and the cluster will completely stop.

 

There are several steps necessary to change the cluster lock disk. The simplest method is to change the VG you have now to a new 1GB disk from your new storage. As before, no need to create an lvol, just the vglock VG and one PV which will be your new lock disk. Be sure you follow all the instructions on how to setup the VG and PV for lock disk support. You will have to stop the cluster in order to change the lock disk information.

 

http://h20564.www2.hp.com/hpsc/doc/public/display?docId=emr_na-c03383413

 

 



Bill Hassell, sysadmin
chindi
Respected Contributor

Re: Cluster vglock Unavailable

Thanks a ton Bill .