On Fri, 9 Feb 1996 [EMAIL PROTECTED] wrote:
We've been successfully using the small DLT stackers with AFS backup for
a while now. This is particularly easy in 3.4 AFS using the callout
routines from butc. We're using our own jukebox driving software that we
wrote here and runs on several different UNIX platforms. We've never
tested this software with the big DLT robots - just the 7-tape stacker
models. I assume it would probably work however. The software is
available on the fermitools home page -
http://www-fermitools.fnal.gov
> Dave >
> We had a look at the DEC DLT towers for using them for Legato and AFS backup.
>
> After a detailed discusseion with one of the DEC guys in product
> support, we ame to the conclusion that it would be quite possible to
> combine the afs3.4 butc callout facilities and Legato Meda and Robot manager.
> But you have to be sensible aabout this and have realistic expectations.
>
> 1) dump is no problem, but one has to find a way to correlate AFS
> tape-labelling and numbering system with Legato's and the organisations
> external tape store
>
> 2) savedb ditto
>
>
>
> 3) readlabel cannnot easily be suported because the essence of the
> command is that one doesn't know the label of a given tape so how would
> one ask the robot to load the tape?
>
> 4) scan tape ditto
>
> 5) writelabel ditto
>
> 6) restoredb must also be a manual operation, you do this when you lost
> your AFS backup database, so who would know the ID of the Ubik_db_dump
> tape to load. This must be a manual operation (get the last Ubik_db_dump)
>
> 7) restore can after some work probably made to work if one first
> determines the tape needed and load them in the tower (probably
> ejecting other tapes)
>
>
> A tricky one and one that you want to work is appendump. Our
> incrementals are fairly short so we want to place several incrementals
> on one tape, but.....
> If you go through the motions you find that when the callout asks for
> appenddump so and so, you have to load the "the last tape used before
> for this series of incrementals" neither the ID passed to the callout
> on appendump, or the fact that others use the same drive since the last
> incremental, so "yesterday's" tape is not in the drive anymore, are helpfull
> Since all problems in IT are solved by adding one additional layer of
> indirection, that what I think is necessary. During a series of
> incrementals, maintain a list of tape-ids (Legato's media managar
> id"s?) used and from that list load the last. If you lose this list
> every now and then is not a real problem as AFS backup's appenddump
> would be happy with a fresh tape in that case. You need to register the
> fact for later restores.
>
> So we will, after we have organised ourselves after the
> re-organisation, first try a single drive DLT and then a robot. Only
> when it have proven it works, we will purchase one.
>
>
> Have fun
>
> Joop Verdoes
>
>
Steve Hanson - FERMILAB, Batavia, Il.
[EMAIL PROTECTED]
