topic MCSG Cluster locks in Operating System - HP-UX

MCSG Cluster locks

Leslie Fischer — Thu, 23 Jun 2005 13:35:17 GMT

We are installing two new servers and plan on running VxVm as the bootable-mirrored-root disk group. We will use VVM to manage the disks instead of Mirror-UX or Online JFS. Also, MCSG 11.16 will be running with a 2 node/1 package failover. My concern is that I have read somewhere in the Veritas Docs that MCSG cluster locks are not support on VvVM root disks. Can anyone confirm this?

I have other systems that are running MCSG 11.16 and in the /etc/cmcluster/cmcmconfig.ascii file, the FIRST_CLUSTER_LOCK_VG is set to /dev/vg01. Can't display info about the logical volume or vg group. Listed /dev/vg01 and there is a /dev/vg01/group and /dev/vg01/lvol1, but there is no disk associated to it. When you do a vgdisplay -v vg01, the response is the "Volume group is not activated" and "Cannot display volume group "vg01"." My OS is on two internal disks, mirrored on a LVM configured 'vg00'

This other Cluster has 3 packages and uses VxFS and LVM disks groups in the packages but not both together in the same package. All of these disks are configured on a EVA3000.

My question is, do I use pseudo LVM volumes as my Cluster Locks? If I am using all VxVM configured disks, is there another way to define Cluster locks when you do not have any LVM disks configured?

Re: MCSG Cluster locks

Kent Ostby — Thu, 23 Jun 2005 13:37:55 GMT

Leslie --

I suspect that the vg01 group does have disks associated (even if the VG isn't active).

Try this:

strings /etc/lvmtab | more

and you will see disks listed after /dev/vg01.

You need to have a real disk in a non-root VG for the cluster lock even if that VG is never activated after the MC/SG set up.

Best regards,

Kent M. Ostby

Re: MCSG Cluster locks

Geoff Wild — Thu, 23 Jun 2005 13:45:47 GMT

From
http://docs.hp.com/en/B3936-90079/apgs02.html

Note: Remember that the cluster lock disk must be configured on an LVM volume group and physical volume. If you have a lock volume group containing data that you wish to move to VxVM, you can do so, but do not use vxvmconvert, because the LVM header is still required for the lock disk.

So, you must have 1 shared LVM disk between the servers for your cluster lock...

Rgds...Geoff

Re: MCSG Cluster locks

A. Clay Stephenson — Thu, 23 Jun 2005 13:55:51 GMT

Plan B. You might consider setting up a Quorum Server. A little Linux box works mighty well for this.

Re: MCSG Cluster locks

melvyn burnard — Fri, 24 Jun 2005 03:18:34 GMT

The Cluster Lock disc MUST be in an LVM VG, that is shared between all nodes in the cluster.
A disk in a VxVM DG is not supported.

As Clay suggests, I recommend you obtain and install the free Quorum Server product on another HP-UX server, or a Linux server.

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

Re: MCSG Cluster locks

Stephen Doud — Fri, 24 Jun 2005 10:19:51 GMT

2 node clusters require cluster arbitration in the form of either an LVM cluster lock volume group comprised of at least 1 LUN, or a Quorum server - software running on a system outside of the cluster.
A quorum server is a more complex to configure, but it can service multiple clusters and is not disk-dependent.
If you have cluster with a lock disk, it can serve as a quorum server for those clusters that do not have LVM-managed disks.

The "Managing Serviceguard" manual tells how to set up a quorum server, and even how to configure it as a package!

http://docs.hp.com/en/B3936-90079/index.html