On Tue, 26 Nov 2002 at 7:30pm, Nitesh Kumar A. wrote

> I am really excited to know more about AMANDA now. 
> 
> What I understand is that, first amanda will take a level 0 backup (full
> backup) and then for the following days, it will take level 1. 

Usually.  If the level 1s get too big, it may "bump" them to 2s or higher.

> If suppose, amanda takes level 0 on sunday and then level 1, with respect
> to 0 on mon/tue/wed/thu/fri/sat. 
> 
> Now I have files named a, b, c, d, e, etc on my filesystem. I have the
> full backup on sunday.
> 
> File "a" is modified on monday, so the level 1 backup on monday will just
> have file "a".
> 
> File "b" is modified on tuesday, so the backup on tuesday will have just
> file "b" but not file "a" due to just level 1 backup.

That's incorrect.  A level 1 backs up everything changed since the last 
level 0.  So Tuesday night's backup will have "a" and "b".

> At some point of time, if I want to backup all the files, then I have to
> contact all the tape drives. Is this the case? Or will amanda tell me on
> which tape drives are these files located? How do I search for a
> particular file in the backup?

The program "amrecover" offers a ftp-like interface to the backups.  You 
tell it what files you want (and from which data), and it'll tell you what 
tapes you need.

> So if just file "a" is written into the tape drive1, how can we use the
> rest of the space on the tapedrive1?

Amanda does not append to tapes -- you'll need to change tapes each day.

For more, please go read the amanda chater from "Unix Backup & Recovery", 
available at <http://www.backupcentral.com/amanda.html> as well as the 
docs in the amanda tarball.  They'll explain a lot of these basic 
concepts.

-- 
Joshua Baker-LePain
Department of Biomedical Engineering
Duke University