topic Re: VAX Multi-Site Cluster in Operating System - OpenVMS

VAX Multi-Site Cluster

crockettcelt — Tue, 04 Oct 2005 10:39:55 GMT

Does anybody know of sites that are still doing VAX-to-VAX multisite clustering? I need to prove to our network group that this can still be done.

Re: VAX Multi-Site Cluster

John Gillings — Tue, 04 Oct 2005 19:23:02 GMT

James,

OpenVMS is OpenVMS. VAX, Alpha or Integrity, the only significant difference is performance and scalability.

The intersite cluster interconnect of choice today is gigabit ethernet. For some older VAXes there may not be a native gigabit adapter, but that doesn't really matter as long as there's some network switch your VAX can connect to which reaches the gigabit.

Provided your VAXes can "see" each other directly, and you satisfy the latency requirements for an OpenVMS Cluster, you can definitely create a VAX only multi site cluster. You can also add Alpha and/or Integrity systems to the same cluster.

Re: VAX Multi-Site Cluster

Bart Zorn_1 — Wed, 05 Oct 2005 02:26:09 GMT

You should also remember that most network groups either do not understand that there is more than tcp/ip or do not want to support anything else but tcp/ip.

For OpenVMS clustering you need a level 2 network connection (aka a bridged VLAN). A level 2 tunnel over ip is probably not an option because it imposes too much latency.

HTH (probably not...)

Bart Zorn

Re: VAX Multi-Site Cluster

Willem Grooters — Wed, 05 Oct 2005 03:39:23 GMT

The network group need to be EDUCATED, not persuaded. It's VMS, so if it worked in the past, it will work today. The only problem you may have is connectivity. 10Mb ethernet (standard on VAX) is not the wisest solution nowadays. But luckily, there are 10/100Mb UTP Ethernet cards for VAX (Not by Digital/Compaq/Hp, obviously, but from Nemonix (http://nemonixengineering.com)) so that shouldn't be the problem.

Re: VAX Multi-Site Cluster

Ian Miller. — Wed, 05 Oct 2005 03:47:31 GMT

FDDI is often used for VAX intersite links.

There are FDDI to ethernet gateways like these http://www.dnpg.com/ which help.

Re: VAX Multi-Site Cluster

Jan van den Ende — Wed, 05 Oct 2005 03:56:13 GMT

James,

technically there are no issues. Period.

Quite another story is organisatorial.

By far the wisest advise I ever received on the topic is the statement (well, call it a conundrum):
The cluster interconnect is _NOT_ a network component, it is the _SYSTEM BUS_,
although it uses network technology, of course.
( (c) Tom Speake, former Manager Disaster Tolerant Computing, DEC)

Try as hard as you can to convince Management that you need some DEDICATED wires, and those should be managed by _VMS SYSTEM MANAGEMENT._

But once again, NO technical issues!

hth,

success.

Proost.

Have one on me.

jpe

Re: VAX Multi-Site Cluster

Willem Grooters — Wed, 05 Oct 2005 04:02:12 GMT

additional:
Cluster traffic is NO IP traffic. SCS is a protocol in itself, and cannot be routed (AFAIK). The VAXen must therefore be connected over ONE network - a connection of their own is the best solution.
This might not exist in the perception of the network group - especially when raised in Windows and Unix environments, their idea of "network" is "IP". That there could be other protocols is beyond their horizon.

Re: VAX Multi-Site Cluster

Michael Yu_3 — Wed, 05 Oct 2005 19:14:40 GMT

Hi,

Back in the old days when we had MDF for VAX(Multi Data Centre Facility), FDDI was a must.

Thanks and regards.

Michael