info-vax@ucbvax.ARPA (03/27/85)
From: Stephen M.King <KING@AFSC-HQ.ARPA> Currently, we have 2 separated 780s running VMS 3.7. We have separate orders in for DecNet/EtherNet, another 780, cluster (SC, 2-HSC, 15 RA-81). Questions: 1. If Cluster arrives first, can we Cluster the 2 780s without EtherNet? 2. Can we cluster anything without VMS 4.0? What do we lose (or how much do we have to backtrack) if we try to implement a cluster using 3.7? 3. Can we operate DecMail, single UAF, etc in a non-EtherNet Cluster? 4. Anyone have a guess as to how many hours we will gain or lose by working with 3.7 and THEN moving to 4.0??? 5. Anything else? Thanks in advance, Steve -------
info-vax@ucbvax.ARPA (03/28/85)
From: LEICHTER <Leichter@YALE.ARPA>
...
Questions:
1. If Cluster arrives first, can we Cluster the 2 780s without EtherNet?
Yes. Ethernet is not required to connect machines over a CI (the cluster
interconnection hardware). In fact, DECnet will run over the CI. (Note:
The CI is much faster than an Ethernet - about 7 times as fast - but is not
designed for general networking. Hence, actual DECnet throughput through a CI
is no better than through the Ethernet. The Ethernet has other uses, too -
LAT runs on Ethernet but not a CI, for example.)
2. Can we cluster anything without VMS 4.0? What do we lose (or how much
do we have to backtrack) if we try to implement a cluster using 3.7?
Here we run into a question of semantics. Yes, VMS V3.x (x>5 or so) supports
the CI hardware - you'll be able to access disks on an HSC using it. But the
support is quite limited: Only one system should try to get write access to
a disk at any one time, and getting even read access to work requires that you
turn off caching for the disks you wanted shared. The reason is the "cluster"
software which is missing from V3.x: The stuff to coordinate accesses by the
various members of the cluster. This isn't in until V4.0. With V3 systems
on a CI, you have a fast communications medium between independent machines.
(I don't think the "DECnet over the CI" works in V3, either.)
What you would lose is mainly the effort of setting up the V3 system - probab-
ly pretty easy to do.
3. Can we operate DecMail, single UAF, etc in a non-EtherNet Cluster?
If it runs in a cluster at all, it should run in a non-Ethernet cluster. Note
that under V3, you can't do a single UAF system - the shared file system is
part of V4.
4. Anyone have a guess as to how many hours we will gain or lose by
working with 3.7 and THEN moving to 4.0???
Depends on what you try to do with 3.7. It's probably worth doing just on
the general principle that you can't have any faith in the new hardware until
you've pounded on it a while.
5. Anything else?
Thanks in advance,
Steve
-------
-- Jerry
-------info-vax@ucbvax.ARPA (03/28/85)
From: (Stephen Tihor) <TIHOR@NYU-CMCL1.ARPA> DECnet over the CI does indeed work under Version 3 (and even between version 3 and version 4 machines, ahtough it required a kludge to make it so) ... indeed as I recall DECnet was the first thing that worked over a CI. There was a brief period when DEC was selling the CI as "get a fast DECnet link now, unshared HSC disks later, shared HSC disks later.....". \\ Stephen Tihor / CIMS / NYU / 251 Mercer Street / New York, NY 10012 // (( DEC Enet: RHEA::DECWRL::"""TIHOR@NYU-CMCL1.ARPA""" NYUnet: TIHOR.CMCL1 )) // ARPAnet: Tihor@NYU-CMCL1 UUCPnet address: ...!ihnp4!cmcl2!cmcl1!tihor \\ -------
info-vax@ucbvax.ARPA (03/28/85)
From: (Stephen Tihor) <TIHOR@NYU-CMCL1.ARPA> ..just realized that someone might misinterpret...DECnet-CI has been pre-kludged by DEC to work betwen any mix of V3 and V4 systems. It certainly works between 3.7 and 3.7 and 3.7 and 4.x and 4.x and 4.x system all at the same time \\ Stephen Tihor / CIMS / NYU / 251 Mercer Street / New York, NY 10012 // (( DEC Enet: RHEA::DECWRL::"""TIHOR@NYU-CMCL1.ARPA""" NYUnet: TIHOR.CMCL1 )) // ARPAnet: Tihor@NYU-CMCL1 UUCPnet address: ...!ihnp4!cmcl2!cmcl1!tihor \\ -------
info-vax@ucbvax.ARPA (03/29/85)
From: dual!mordor!seismo!harvard!bu-cs!todd@BERKELEY (Todd Cooper)