Path: utzoo!utgpu!watmath!clyde!att!rutgers!mit-eddie!uw-beaver!cornell!batcomputer!itsgw!steinmetz!uunet!mcvax!cernvax!achille
From: achille@cernvax.UUCP (achille)
Newsgroups: comp.sys.apollo
Subject: Re: more SR10 questions
Message-ID: <896@cernvax.UUCP>
Date: 3 Dec 88 16:56:05 GMT
References: <152@nrl-cmf.UUCP> <15471@iuvax.cs.indiana.edu>
Reply-To: achille@cernvax.UUCP ()
Organization: CERN European Laboratory for Particle Physics, CH-1211 Geneva, Switzerland
Lines: 36

In article <15471@iuvax.cs.indiana.edu> jec@iuvax.UUCP (James E. Conley) writes:
>
>	You'll have to abandon them for another vendor... SR10 does not include
>dump, restore, or their remote versions.  This makes some sense if you allow
>for Apollos different file system formats, but it is still a pain since wbak
>and rbak are pretty primative (and slow).
>
Actually, I'm using almost daily both (dump+restore) and (r/wbak). Wheter I agree
that w/rbak are painfully slow, they actually allow you to save AND restore your
files in a PREDICTABLE way. The same is not true for dump and restore.

One of the biggest problems with dump is that it does not produce a list of saved
files, how do you know a few weeks after the backup, which file is on which tape ?
Also, dump stores files in 'random' order on tape (I think is disk block ordering),
if you want to restore 2 files that were in the same directory, chances are they are
NOT in the same tape (yes, we have dumps that span up to 20 IBM 3480 cartridges).
Can you imagine the pleasure of mounting 20 cartridges to find out the file you
want on the last tape ? With the wbak output, I can just pick up the right tape
and read only that one !

I care about the backup speed, but I also think that speed is not everything !
Your information should not only be saved, it should also be retrievable !
It should be a easy task to do that, operators should be able to do it !

Do you know that after restoring a full dump, you are supposed to run a.s.a.p
another full dump ? that's what the Cray doc says, not a decent explanation
about this requirement. Why ? 

I think dump and restore are pretty awkward pieces of software, they are just fast,
I would stop using them tomorrow if had w/rbak on the Cray.

Probably Apollo hasn't produced very remarkable software, but w/rbak are real
neat (as functionality if not as speed) and that should be said.

Achille Petrilli
Cray & PWS Operations