topic Re: Quorum fix in DECamds works? in Operating System - OpenVMS

Quorum fix in DECamds works?

Jan van den Boogaard — Thu, 20 Oct 2005 08:54:22 GMT

Hi all,

Has anyone used the quorum fix option in DECamds successfully? I couldnt get it working in a test-cluster, so am I overlooking something?

I tried it using DECamds data analyzer on a node outside the cluster AND on a node within the cluster.

Greets,
Jan

Re: Quorum fix in DECamds works?

Volker Halle — Thu, 20 Oct 2005 09:08:34 GMT

Jan,

I'm sure I've demonstrated this once or twice over the years...

- do you have write access to the target node from your data analyzer node ?
Test it with trying to force an image exit or modify quotas for a process on that node. Use REPLY/ENABLE on the target node to check the RMDRIVER message.

- what state is the cluster in ? Note that you cannot 'fix quorum' if the node has never joined an existing cluster (i.e. boot one single node with VOTES=1 and EXPECTED_VOTES=2)

Volker.

Re: Quorum fix in DECamds works?

Andy Bustamante — Thu, 20 Oct 2005 22:35:42 GMT

I use the Availablity Manager running on a non VMS box to help manager systems. The adjust quorum works very well. I believe you need "Control" access to adjust quorum and crash a node. See SYS$MANAGER:AMDS$DRIVER_ACCESS.DAT for the configuration. You'll need to restart AMDS to load a configuration change.

If your cluster doesn't have quorum, you won't be able to adjust quorum from any node in the cluster, the trigger needs to come from outside the cluster.

Andy

Re: Quorum fix in DECamds works?

Jan van den Boogaard — Fri, 21 Oct 2005 02:27:56 GMT

Thanks Andy and Volker

I tried the quorum fix in Availability manager from a OpenVMS node outside the cluster and it worked ok, after I set the access to W (write) in AMDS$DRIVER_ACCESS.DAT (something like *\password\W ).

I'll try AMDS later on.

By the way, am I right in that the Quorum fix can ONLY be one from a node outside the cluster?

Greetings , Jan

Re: Quorum fix in DECamds works?

Volker Halle — Fri, 21 Oct 2005 02:31:13 GMT

Jan,

if the cluster has lost quorum and your AMDS/Availability Manager data analyzer node would be part of that cluster, it will also hang (waiting for quorum to be regained) and you can't use it...

Volker.

Re: Quorum fix in DECamds works?

Volker Halle — Fri, 21 Oct 2005 02:35:50 GMT

Jan,

AMDS$DRIVER_ACCESS.DAT (something like *\password\W ).

Please consider to make your AMDS security a little less generic by adding an ethernet or DECnet address (of each of your possible data analyzer nodes) instead of the wildcard '*'.

Volker.