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VMS Cluster

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Mulder_1
Frequent Advisor

VMS Cluster

A quick question :

If a node which was already in cluster,now made shutdown and another node with a different name and with same decnet address is tried to boot, will the node boot ?

Answer : No,it will be in hung state as connection manager will not allow it to boot (tested already).

My question is :
If at that instance,the old node which has been shutdown,is de-registered and the session control entries are flushed out ( MCR NCLflush session control naming cache entry "*" ) and re-register the new node, will the new node be added as a vaild cluster member ?

Thanks
5 REPLIES
Kumar_Sanjay
Regular Advisor

Re: VMS Cluster

Hello FOX2,


Have you check the value of Votes and Expected Votes..is it correct ?



Jan van den Ende
Honored Contributor
Solution

Re: VMS Cluster

FOX2,

>>>
If at that instance,the old node which has been shutdown,is de-registered and the session control entries are flushed out ( MCR NCLflush session control naming cache entry "*" ) and re-register the new node, will the new node be added as a vaild cluster member ?
<<<

That is a definite NO.
The combo nodename<>SCSSYSTEMID is kept in CLUSTER_AUTORISATION.DAT, and matches of one of those MUST match the other.
And SCSSYSTEMID is a direct 1:1 with the DECnet address, so...
Alas, NOT without a fresh cluster-config.

Proost.

Have one on me.

jpe
Don't rust yours pelled jacker to fine doll missed aches.
Robert Gezelter
Honored Contributor

Re: VMS Cluster

FOX2,

My suggestion would be to use a different DECnet address/SCS ID. To prevent confusion, do not change the connection between DECnet node name and DECnet address.

If there are functions that need be done by particular members of the cluster, use a logical name (system or cluster-wide) to identify which nodes should do that function.

This is far safer for long term operations.

- Bob Gezelter, http://www.rlgsc.com
Andy Bustamante
Honored Contributor

Re: VMS Cluster

As Jan points out, the DECnet address and and nodename are tracked while the cluster is formed. You can remove a node1 and reboot a new node1-new with the same name and SCSSYSTEMID as node1 but you cannot change the the pairing on a node without rebooting the cluster.

Andy
If you don't have time to do it right, when will you have time to do it over? Reach me at first_name + "." + last_name at sysmanager net
Hoff
Honored Contributor

Re: VMS Cluster

The OpenVMS manuals are located at http://www.hp.com/go/openvms/doc

This stuff works just fine with native DECnet-Plus and you can add the node back in without issue, assuming the site is using native addressing. With DECnet-Plus using its native addressing, the DECnet host address is not tied to scssystemid in any way.

If you're using DECnet Phase IV addressing with your DECnet-Plus installation on the other hand (and as appears potentially the case, given your goal of re-using an address), then see the herd of answers here, and the manuals, and other related topics. Short answer: nope. can't do that. Either reboot the whole cluster, or pick a different scsnode/scssystemid pair and a different Phase IV address.

The obvious search (for the string scssystemid) in the PDF of the OpenVMS cluster manual shows the following (slightly reformatted for inclusion here) details on page 4-3:

----
What is the nodeâ s DECnet node name?

If the node is running DECnet, this prompt, the following prompt, and the SCSSYSTEMID prompt are displayed. Enter the DECnet node name or the DECnetâ Plus node synonym (for example, JUPITR). If a node synonym is not deï¬ ned, SCSNODE can be any name from 1 to 6 alphanumeric characters in length. The name cannot include dollar signs ( $ ) or underscores ( _ ).

SCSNODE


What is the nodeâ s DECnet node address?

Enter the DECnet node address (for example, a valid address might be 2.211). If an address has not been assigned, enter 0 now and enter a valid address when you start DECnet (discussed later in this chapter).
For DECnetâ Plus, this question is asked when nodes are conï¬ gured with a Phase IV compatible address. If a Phase IV compatible address is not conï¬ gured, then the SCSSYSTEMID system parameter can be set to any value.

SCSSYSTEMID
----