backing up several machines to one tape?

[Craig Lanning <CLanning@pdesds1.atg.trc.scra.org>]

    Date: Fri, 30 Apr 1993 01:50 EDT
    From: kmp@harlequin.com

	Date: Thu, 29 Apr 1993 20:46 EDT
	From: K. Mark Alexander <kma@samson.cadr.amis.com>

	... The real question is: How do you retrieve from a specific hosts' lmfs
	backup dump?

    Speaking of "how do you retrieve", I recently contemplated buying an
    exabyte drive for my Macivory and was independently warned by several
    people that (in their opinion) exabyte is a terrible medium in which to
    do backups.  The word I got is that people have found it to have
    higher-than-average risk of not being able to retrieve data from at all,
    and that it's especially bad in the case where you're reusing the same
    tape over and over (as one would presumably do with incrementals).  I
    didn't try it myself, so this is third-hand info at best, but it's worth
    actually checking some of your exabyte backups before you are desperate
    for them to convince yourself that they're really storing your data in a
    retrievable way.  Personally, I wish smbx would provide support for DAT
    drives, which are more popular, more widely available, much cheaper, and
    reputed to be more reliable.

The Exabyte tapes seem to be fairly reliable.  I backup my XL1200 onto
one every week and we backup several Gigabytes worth of Sun and DEC
filesystems onto them each day.  The real important thing to remember is
that Exabyte drives show the effects of dirty heads sooner than other
drives so it is very important to clean the drive regularly.
Fortunately, Exabyte produces their own head cleaner which makes the job
very easy (you put the cleaning tape into the drive and it does the
rest).

Craig Lanning <CLanning@trc.scra.org>
Grumman Data Systems
North Charleston, SC