Operating System - OpenVMS
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OpenVMS Cluster details

Occasional Contributor

OpenVMS Cluster details

Hi all,


I am trying to find a DCL command to display an OpenVMS Cluster name or internal cluster identifier... something to uniqely identify an OpenVMS cluster. I have tried SHOW CLUSER and SHOW SYSTEM/NOPROCESS/CLUSTER/FULL but neither of these displays the output I am looking for.

Is there any command I can execute to display these cluster details on OpenVMS?


Respected Contributor

Re: OpenVMS Cluster details

I'm not sure what lebvel of detail you would like, so try teh following:


From a terminal window set to 132 characters (  for better visibility) use SHO CLUSTER/CONT

This will show you a continuous view ofthe cluster.  From the command prompt type "HELP FIELDS"

This will display the field names that you can "ADD" to the display.  Choose the fields that will present what you need.




Volker Halle
Honored Contributor

Re: OpenVMS Cluster details

There is the Cluster Group number, which is shared by all members of the cluster and must be unique within the LAN, to which the cluster members are connected.





Duncan Morris
Honored Contributor

Re: OpenVMS Cluster details

Hi Petrus,


welcome to the forum!


The unique feature of the cluster is the cluster group number.


See http://h71000.www7.hp.com/doc/731final/4477/4477pro_021.html#lavc_mi_security for details on setting the group number and/or password.


The cluster authorization file, SYS$COMMON:[SYSEXE]CLUSTER_AUTHORIZE.DAT, contains the cluster group number and (in scrambled form) the cluster password.


You can dump this file to show the cluster group number.



John Gillings
Honored Contributor

Re: OpenVMS Cluster details

Although there are several identifiers that should be unique in a cluster, there's no single entity that is guaranteed. The cluster group number is a good choice, but there's no simple way to find it without parsing output. Volker's answer is the best way to find it




You could read the (binary) cluster authoration file, but that's a bit messy. There may still be clusters which don't have a group number, though they'd be fairly rare these days (CI or DSSI interconnects only).


In DECnet days you could define a cluster alias, but it wasn't mandatory.


Something unique, guaranteed to exist, easy to find on any random node? That's tricky.


One approach would be to define something yourself, or to use the node name or address, with a mapping to a name for the cluster it belongs to. A few tools that might help:


F$GETSYI("CLUSTER_MEMBER") will return TRUE if the node is a member of a cluster

Logical names SYS$NET_SERVICES_* contain network names and address

(on Integrity systems only) F$GETSYI("SYSTEM_UUID") returns an unique ID for the system

A crucible of informative mistakes
John McL
Trusted Contributor

Re: OpenVMS Cluster details

Can you please explain why you want this information.


I'm wondering if you want to simply post a cluster name on some display or report, in other words purely for information and identification.


If that's the case then I suggest that you define a cluster name cluster-wide and simply access that logical name (e.g. DEF/CLUSTER CLUSTER_NAME CLUSTER_1).


Just be aware that the cluster-wide logical will disappear if all machines in the cluster are shutdown, so it makes sense to have in SYSTARTUP a few lines that test if the cluster name exists and if not define it.  Where would I store such a name?  In SYS$MANAGER (or at least a SYS$STARTUP directory) for the cluster, maybe use the cluster number mentioned above either as part of the name or as a means of mapping to a name.


Occasional Contributor

Re: OpenVMS Cluster details

"From a terminal window set to 132 characters" 


How do I set the line length for my session? DCL command? ..and what is the maximum?

Honored Contributor

Re: OpenVMS Cluster details

>>> "From a terminal window set to 132 characters" 

>>> How do I set the line length for my session? DCL command? ..and what is the maximum?
It's not obvious to me, what you mean with a "line length for my session". The "set to 132 characters" referred to the DCL command:  $ set terminal/width=132
The maximum width for a terminal depends on your terminal (emulation). My xterm has no problems with /width=200.