Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site ucbvax.ARPA Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!ucbvax!info-vax From: info-vax@ucbvax.ARPA Newsgroups: fa.info-vax Subject: Re: Need Some Info!??? Message-ID: <5836@ucbvax.ARPA> Date: Wed, 27-Mar-85 17:41:57 EST Article-I.D.: ucbvax.5836 Posted: Wed Mar 27 17:41:57 1985 Date-Received: Thu, 28-Mar-85 06:47:19 EST Sender: daemon@ucbvax.ARPA Organization: University of California at Berkeley Lines: 46 From: LEICHTER ... 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 -------