On Tue, Aug 31, 2004 at 04:29:43PM -0400, Joe Konecny wrote:
> Jon LaBadie wrote:
> 
> >>So... is amanda really not made for disaster recovery?  That's great
> >>that it will back up to a holding disk with no tape but if the hard
> >>drive dies it's rather meaningless.
> >
> >
> >How does that imply "not for disaster recovery"?  What would
> >your current system do if the tape "jammed"?  Would it still
> >backup?  True, if you encountered a situation where you did
> >not put in a tape AND the holding disk died you would not
> >have a backup.  Is that your concern?
> >
> 
> It's because of what I am used to...  Right now Arcserve
> backs up my Netware server as long as there is a tape in
> the drive.  To me that's ideal since the data collection
> in our factory runs 24-7.  Even on Sat and Sun when I'm not
> there the tape is still over written with the latest data.
> If Amanda does only copies the data to a holding area and
> we lose a drive on Sunday night I have massive problems.
> That's what I call a disaster and I don't see how amanda
> can help me there.  I do want to make it work however.
> 

For the disaster you feel is possible several things have
to occur at the same time.

  1. Your tape or tapedrive fails, or you do not put in a
     suitable tape - though as has been said by another,
     with a tapecycle of 1, you could override that protection.

  2. A drive containing valuable data would have to fail

  3. The drive containing your holding disk would have to fail.
     Usually this is not the systems primary data drive.  And
     it can also be spread over multiple drives so if one fails
     others will do the job.

What about your current system.  Fine, if the wrong tape is
inserted you still get a current backup.  Same with amanda.
It is just on the holding disk.

And I'd be worried about something else in your current system.
Presently I'm starting to "wear out tapes".  Suppose you forgot
to change a tape, I'm guessing the tape left in there has the
most current backup and is about to be overwritten by the new
backup.  What if the tape fails, or the backup fails in the
middle for some other reason.  You will have neither todays
nor the last backup.

-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
 JG Computing
 4455 Province Line Road        (609) 252-0159
 Princeton, NJ  08540-4322      (609) 683-7220 (fax)