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OpenVMS registry/s in a cluster?

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Dave Gudewicz
Valued Contributor

OpenVMS registry/s in a cluster?

Need some clarification please.

3 node Alpha 7.3-2 (fully patched) cluster.

2 systems (say A & B) share a system disk, the 3rd node ( C ) has its own system disk and is currently running Advanced Server v7.3B.

Is it possible to have 2 registries in the above configuration because of the >1 system disks? In other words, leave the 3rd (C) node's registry as is, and have another for the remaining 2 (A&B) nodes.

Doc says that the registry is a clusterwide database structure, but I'm wondering if they aren't referring to a common system disk cluster or not. And no, I don't have another cluster to test this on.

TIA, Dave...

Honored Contributor

Re: OpenVMS registry/s in a cluster?

I'm somewhat skeptical around having multiple registry files; with various cluster-aware environments, that sort of thing can trigger badness. I'd want to test that, to ensure things didn't go weird. (The queue manager, for instance, can sometimes go weird when there are disparate queue managers running within the same cluster.)

As for the general set-up, configure the SYS$REGISTRY logical name and related baggage to the location of the file per:


and off you go. (I'd probably look to create anew, or to promote the current registry to the cluster registry; to set it up as the shared registry.)

And I'd suggest folks get, borrow, lease or otherwise get some scratch Alpha boxes here. Or the CHARON-AXP emulation. Low-end Alpha boxes or low-end Itanium boxes (which would send you into CIFS/Samba land) are cheap, and can easily be cheaper than disrupting production.

John Gillings
Honored Contributor

Re: OpenVMS registry/s in a cluster?


This is yet another piece in the "cluster personality" puzzle. If you use the registy, it must be physically cluster common.

See SYLOGICALS.TEMPLATE. It's probably the most complete list of files that should (or in many cases MUST) be physically shared across a cluster.
Single system disk clusters work fine OOTB, but for multi system disk clusters, every system manager is expected to carefully read several manuals, and work out how to implement their own mechanisms. It's very hard to get it right, and more often than not, everything seems to "work" until something goes wrong.

Maybe one day OpenVMS engineering will fix this by implementing a proper clusterwide database management utility dealing with configuration, backup, restore, adding and removing nodes etc.

(bangs head against this wall yet again...
A crucible of informative mistakes
Anton van Ruitenbeek
Trusted Contributor

Re: OpenVMS registry/s in a cluster?


If you're having a cluster with more than one system disk (because you have multiple hardware, cheographicly needs or else) you MUST create a common disk (not the systemdisk of eather nodes) wich contains ALL your cluster common things. In a proper environment you shadow this drive over or the systems or over the boundaries. This common drive contains all your clusterwide configurations. Eg. clusterwide TCP/IP configuration, bootprocedures, authorize etc.
If you are lucky and can confince your management, you can add a fourth disk for all the programs on the cluster (this wil result in a smaller third ofcourse). If not, this third drive is your place for cluster common programs. In this way, if one node goes down, you don't hooked up with a hanging system because possible information is on another drive or so.

This was actualy done at the cluster of the Amsterdam Police Dep. and proved itself several times (eg. some people powered down the wrong part of computerroom and other interruptions).

NL: Meten is weten, maar je moet weten hoe te meten! - UK: Measuremets is knowledge, but you need to know how to measure !
Dave Gudewicz
Valued Contributor

Re: OpenVMS registry/s in a cluster?

Thanks for all the (very) informative replies.

One registry file, here we come !

Paul Nunez
Respected Contributor

Re: OpenVMS registry/s in a cluster?


The only OpenVMS application that uses the registry is Advanced Server. Since node C is the only node running Advanced Server, you only need to run the registry server on node C.

The registry_server processes in a cluster use a coordinate lock to control which cluster member is the "master". The master services all registry requests from all cluster members (the other cluster members running the registry_server are sitting idle waiting to acquire the lock should the current master go down). So, yes, the must all use the same location for SYS$REGISTRY:.

Running the registry_server on nodes which are not Advanced Server nodes could incur a slight performance penalty if one of them becmes the registry master. On the other hand, for redundance purposes you may want to start the registry server on all nodes, but try to fanagle things so the master is typically the Advanced Server node (something easier said than done).


Dave Gudewicz
Valued Contributor

Re: OpenVMS registry/s in a cluster?

Thanks for the info Paul.

In this case, Advanced Server will be running on all 3 nodes. Today its only running on node C. The other 2 nodes (A&B) have the REGISTRY_SERVER process running and they are using COM, which requires the registry I'm told.

A&B had Advanced Server v7.3 installed and running at one point in time, not now.

I plan on updating A&B to v7.3B as is currently running on C and was a little fuzzy on the registry requirements for a cluster with separate system disks.

Previous answers lifted the fog.