topic Re: 4 node cluster lockdisk in Operating System - HP-UX

4 node cluster lockdisk

joe_91 — Tue, 07 Feb 2006 14:35:47 GMT

I am being told that i cannot use a lockdisk on a 4 node cluster. Could someone explain why and what are the limitations of using lockdisk?

THanks

Joe

Re: 4 node cluster lockdisk

Steven E. Protter — Tue, 07 Feb 2006 14:36:42 GMT

You have received correct advice.

You need a quorom server

http://h20293.www2.hp.com/portal/swdepot/displayProductInfo.do?productNumber=B8467BA

SEP

Re: 4 node cluster lockdisk

Luk Vandenbussche — Tue, 07 Feb 2006 14:41:07 GMT

Hi Joe,

You can use a cluster lock disk on a cluster with maximum 4 nodes

See p 68 on

http://www.docs.hp.com/en/B3936-90095/B3936-90095.pdf

Re: 4 node cluster lockdisk

A. Clay Stephenson — Tue, 07 Feb 2006 14:41:16 GMT

Normally a cluster lock (even a Quorun server) is not required on a 4-node cluster unless there is a significant probability that the cluster will be split exactly in half.

Re: 4 node cluster lockdisk

joe_91 — Tue, 07 Feb 2006 14:50:50 GMT

All:

So let me summarize as i understood.

1 node cluster - no lock disk
2 node cluster - lock disk must
3 node cluster - lock not required
4 node cluster - lock not possible (quorum server may be used)

Thanks

Joe

Re: 4 node cluster lockdisk

Mark Nieuwboer — Tue, 07 Feb 2006 15:13:53 GMT

Hi joe,

1 a one node cluster don't excist.
2 correct
3 correct
4 not correct. You can have a cluster lock disk. Only the cluster lock disk must be in a volumegroup known on all the servers.
Or you can choose for a quorom server.

grtz. Mark

Re: 4 node cluster lockdisk

melvyn burnard — Tue, 07 Feb 2006 17:40:35 GMT

That is incorrect.
If not using a Quorum Server, a Cluster Lock Disc is MANDATORY for a two node cluster, recommended for a 3 or 4 node cluster, but is unsupported for 5 nodes and above
So to use your summary:

1 node cluster - no lock disk
Correct
2 node cluster - lock disk must
Correct
3 node cluster - lock not required
Correct
4 node cluster - lock not possible (quorum server may be used)
Incorrect

Also, if you are at the planning stages of building a cluster, I would recommend you go down the route of a quorum server for a number of reasons, and although old, this document may help explain the differences between Cluster lock technologies used:
http://docs.hp.com/en/B3936-90078/B3936-90078.pdf

or pages 69-75 of
http://docs.hp.com/en/B3936-90095/B3936-90095.pdf

Re: 4 node cluster lockdisk

Steven E. Protter — Tue, 07 Feb 2006 18:37:21 GMT

The original advice was correct.

Melvyn is the forums expert on the topic and he confirms with more detail my original post.

Good Luck,

SEP