[comp.os.vms] LAVC info request

oberman@LLL-ICDC.ARPA.UUCP (05/20/87)

>We currently have a number of uVAX-II's, and are thinking of adding more.
>They are used for simulations, VLSI design etc. (for some of which the
>tools are only available on VMS), plus general editing, mail, etc..
>
>Clustering looks a good idea, both in reducing the need for separate large
>disks and in reducing the system management time that having lots of separate
>machines involves.   There should also be availability gains.   So I've been
>waiting for DEC to offer clustering on the Ethernet for years.
>But now they have - should we buy?
>
>DEC have told me the advantages, but are there disadvantages too?  DEC have
>warned that the Ethernet load would be high, so we'd need a bridge to keep that
>off the rest of our net, but what about performance and load on the 'boot
>member'?   And are there any less obvious problems?     We do not want to go
>through all the trouble of converting to LAVC then find we have to revert!
>
>Any advice and experiences - good or bad - from those who have already gone
>LAVC would be most useful.           Thanks.

We've been running LAVC for some time and are very happy with it. Most
everything you are worried about is not much of a problem.

If you have enough LAVC traffic, you will want a bridge. The load on the
boot load is not very high EXCEPT when satellites boot. If several nodes
boot at once the boot node is useless for several minutes.

The real problem is with single  point failure. If the boot node or boot disk
fails, everything dies. I believe V4.6 allows more than one boot disk. If this
is true, things will be much more bullet proof. But don't expect the
reliability of CI clusters.

To put it simply, if DEC stopped supporting LAVC, I'd be in a LOT of trouble.

					R. Kevin Oberman
					Lawrence Livermore National Laboratory
					arpa: oberman@lll-icdc.arpa
					(415) 422-6955

Disclaimer: I an not endorsing any product. I work for Uncle Sam and to
do so would make him upset. I further take no resposibility for the accuracy
of this information. I believe it is correct, but if it's not I can only
say "Sorry".

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