Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watmath!clyde!rutgers!ames!ucbcad!ucbvax!decvax!tektronix!tekcrl!tekfdi!videovax!stever
From: stever@videovax.UUCP
Newsgroups: comp.unix.questions,comp.sources.wanted
Subject: Re: Backup Utilities for Unix
Message-ID: <4385@videovax.Tek.COM>
Date: Tue, 12-May-87 13:52:01 EDT
Article-I.D.: videovax.4385
Posted: Tue May 12 13:52:01 1987
Date-Received: Fri, 15-May-87 06:46:47 EDT
References: <1308@ci-dandelion.UUCP> <4360@videovax.Tek.COM> <2653@cit-vax.Caltech.Edu>
Reply-To: stever@videovax.Tek.COM (Steven E. Rice, P.E.)
Organization: Tektronix Television Systems, Beaverton, Oregon
Lines: 41
Keywords: system management backups dump restore
Xref: utgpu comp.unix.questions:2002 comp.sources.wanted:1017

In article <2653@cit-vax.Caltech.Edu>, Don Speck (alias
mangler@cit-vax.Caltech.Edu) writes:

> In article <4360@videovax.Tek.COM>, stever@videovax.Tek.COM (Steven E. Rice, P.E.) writes:
>> One feature
>> that would be invaluable is the ability to back up the filesystem while
>> the machine is loaded with users and running.
 
> This is not generally workable.  Consider a filesystem with three
> directories, A, B, and C.  After the hypothetical backup program
> finishes looking through A, and is busy looking through B, some
> user moves a file from C to A.  It will not be backed up.  You
> can also work it the other direction, and get two copies of the
> file.  . . .

But in fact, it is generally workable!  In the worst case, you get no
backup, which is just exactly what happens right now [ 8^( ].  In all
other cases, there is at least one backup [ 8^) ].  And unless the
file that was moved and missed being backed up is moved every hour on
the hour (or twice a day, or however frequent the backup is), it will
get caught the next time around.

The frustration I have with all this "modern," "friendly," "powerful"
software is that the backup system I have described was running on the
Scientific Data Systems (SDS) Sigma 7 (later Xerox Sigma 7, then
Honeywell Sigma 7, but that's another story. . .) that was installed
at Montana State University, Bozeman, Montana, in 1967!!!

In all the years I spent pounding on the Sigma 7 (1969 to 1975), the
most I ever lost was 2 hours of work (a crash occurred just as an
incremental backup tape was being mounted).  On a VAX which is brought
down for an hour each evening for incremental backups, a crash can
easily cost an entire day's work.

Perhaps by 1990 we'll be able to catch up to where we were in 1970???

					Steve Rice

-----------------------------------------------------------------------------
new: stever@videovax.tv.Tek.com
old: {decvax | hplabs | ihnp4 | uw-beaver | cae780}!tektronix!videovax!stever