Re: How uses Amada a tapechanger?

On Sun, Oct 03, 2004 at 03:35:30AM +0200, Thorsten Bremer wrote:
> Hello,
> 
> until now I'm using a single DDS-3 DAT-streamer with Amanda and
> everything works well. But it is annoying for me, to change the tape
> every day. Sometime I'll forget this or I'm not at home. So it is
> possible that a lot of backups are collecting on the holding disk.
> 
> I could buy a used "ADIC FastStor DLT 4000"-tapechanger (For 7
> cartrigdes, each 20 GB native capacity). Is it possible to use this
> tapechanger together with Amanda?
> 
> After reaging the docs I also didn't understand, HOW Amanda could use
> a tapechanger: Is it possible, that I could say, that he should use 2
> tapes per tape-run, to save 40 GB on 2 tapes?
> 
> Or is a tapechanger only 7 single tapes for Amanda? And the only
> difference is, that a machine automatically change the tapes every day
> (instead of me)?

Couple of things here:

If things are collecting on your holding disk, you can move them to
a tape with "amflush".

You can also set a parameter in amanda.conf, "autoflush" to ?yes or
?true and during any dump, whatever is left on the holding disk
will be taped along with the new dump stuff.

Yes, of course you can use a changer.  Amanda is used in large
installations doing hundreds of GB backups daily.  They don't
have someone sitting around waiting to change tapes.  Even I
don't do that in my home office.  I have a six position changer
that does 12GB/tape.  I set it to use two tapes -- if it needs
to use them.  I.e. my normal nightly backup is about 7 or 8GB.
But if something unusual happens, it may take over 12GB.  In
that case it will use a second tape.

To start using a changer you must:

- get the changer recognized by your OS
- get the tape drive in the changer working with dd, tar, mt, etc.
- get the changer mechanism working with mtx or some other system cmds.
- select an appropriate changer script, chg-scsi, chg-zd-mtx, chg-mtx
  or some such.
- set several parameters in amanda.conf
- set several parameters in the changer script
- confirm that you can manipulate the changer with amanda tapes
  using the ammt and amtape commands.
- confirm that amcheck can find the next tape.
- do your dumps

-- 
Jon H. LaBadie                  jon AT jgcomp DOT com
 JG Computing
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