On Thu, Nov 03, 2005 at 04:20:10PM +0700, Olivier Nicole enlightened us:
> Stefan,
> 
> > i.e. its impossible to say to amanda to flush some backups on the
> > holding disk to the _current_ tape ?
> 
> I am not sure what you call the current tape, amanda is a sort of
> batch processing, you order a job, it uses one tape for that job, and
> then the next job goes on the next tape.
> 
> The case that often happens to me:
> 
> Monday amanda dumps on tape 1
> 
> Tuesday is holiday, dumps to holding disk
> 
> Wednesday is holiday, dumps to holding disk
> 
> Thursday first thing, I amflush, it writes onto the tape number 2 the
> dumps of Tuesday and Wednesday
> Later on Tuesday i do a normal amanda dump that use tape 3
> 
> And in fact I don't really care what tape is being used, if I need to
> recover something amanda will look through the index and telll me what
> tape I need.
 
Olivier is right. Amanda will write to a tape, and will not write to that
tape again until at least "tapecycle" tapes have been used (tapecycle being
defined in amanda.conf). 

It is an intentional safeguard that amanda will not overwrite "active" tapes
(those that have been written less than "tapecycle" tapes ago) to prevent
loss of data. After all, having good old data is better than having none at
all. 

As for flushing, I have LTO tapes which hold 100GB. After compression, I
backup between 10-15GB per night. It usually adds up to just over 100GB, so
I set autoflush to yes in my amanda.conf, and put a new tape in every week.
I leave that tape in until the end of the week so that if I need to do a
restore, it's there and ready to go. 

Matt

-- 
Matt Hyclak
Department of Mathematics 
Department of Social Work
Ohio University
(740) 593-1263