Jon,
Thanks for the 101 course -- that was very helpful. I'm now wondering
if amanda is what I really need. I have a 90 GB single-tape drive and
(currently) about 15 GB of uncompressed files (from du -k) to be backed
up. Incremental backups should be in the 10-50 MB range (uncompressed).
And to top it off, it's (currently) a single client machine. So a
single tape should last me a long time! I want a low-maintenance
automated backup system that will just email me when I've filled a tape
and need to stick in a new one. Perhaps amanda is way overkill for me
right now. Can anyone suggest an alternative? Hopefully one that is
exceedingly simple for a novice to operate?
Keith.
> -----Original Message-----
> From: owner-amanda-users AT amanda DOT org
[mailto:owner-amanda-users AT amanda DOT org]
> On Behalf Of Jon LaBadie
> Sent: Wednesday, December 21, 2005 2:37 PM
> To: amanda-users AT amanda DOT org
> Subject: Re: Do Overs
>
> On Wed, Dec 21, 2005 at 11:58:05AM -0800, Keith Nicewarner wrote:
> > I'm new to backups (much less Linux or AMANDA), so forgive me if I'm
> > missing some basic concepts.
> >
> >
> > .... I think I've resolved the last issue, but here's the
> > annoying thing: It keeps wanting me to put in a new tape -
> > even though the previous tape wasn't full or even used.
> > Is this normal?
>
>
> OK, basic concepts 101 on tape usage.
>
> Amanda only overwrites tapes, it never ever ever appends
> to the end of a tape it used in an earlier session. So
> don't even think about running amdump today, sending the
> data to a tape and then adding tomorrows run to the same tape.
>
> Early in a dump run amanda will see if it has a valid tape
> to use. When it does find one it writes some amanda metadata
> to the start of the tape (aka the amanda tape header). As far
> as amanda is concerned, any data that was on that tape before
> this is gone, even if it doesn't write any backup data to the
> tape. I.e the tape has been "overwritten", the data is gone.
> Amanda can also free up the index files and logs for the earlier
> dump on that tape.
>
> Amanda expect you to label and rotate the usage of a number
> of tapes. The number of tapes is your choice, but a good
> rule of thumb for the minimum suggested is 1 plus twice the
> number needed for taping a dumpcycle. I have a dumpcycle of
> 7 days, 6 runs per dumpcycle and I generally use only one tape
> per run. So my minimum according to that formula is 1 + 2 * 6,
> 13 tapes. Remember that is a recommended minimum, I actually
> rotate 24 tapes.
>
> You inform amanda of how often it can reuse tapes with the
> tapecycle parameter. If you set tapecycle to 5, then it can
> not reuse the last used tape until 4 other tapes have been used.
> Tapecycle does not have to match the actual number of tapes in
> rotation. My tapecycle parameter is 18 though I rotate 24.
> This lets me gracefully handle (i.e. no action on my part)
> situations like the occasional dump that needs two tapes to
> compete or the occasional failed tape.
>
> > Since I haven't really gotten a good backup, how can I
> > start fresh? It won't let me reuse the test tapes.
> > How can I wipe the tapes clean and make AMANDA think
> > it's the first day of operation?
> >
>
> To reuse a tape, use amrmtape then relabel it (probably -f option).
>
> I once ran a script to refresh a config directory to starting
> state. But it was a long time ago, so no guarentees. I think
> it removed the logs, reports, curinfo, and indexes. In my case
> I keep these in separate directories under the config root so
> it was easy. Optionally I also I recreated, from previously
> saved copies, tapelist, amanda.conf, changer.conf, ???
>
> --
> 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)
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