On Thursday 10 May 2007, R Ransbottom wrote:
>I have gotten so far as getting my first vtape written
>and have lots of questions brewing.
>
>The web docs suggest splitting up your vtape space
>into vtapes of the same size.  Is this required; doe
>Amanda intelligently handle vtapes of various sizes?
>
>Be well,
>rir

Amanda handles vtape with the same intelligence it uses on a regular fixed 
size tape.  Amanda will promote a full backup that isn't quite due in order 
to help maintain an approximately equal tape usage every night.  In fact, for 
those that come into the amanda arena, expecting to be able to do 
incremental's monday-thursday, and a complete full on friday nights are in 
for a somewhat rude shock because you have to bend over backwards, and write 
scripts that beat her about the brow in order to achieve that hugely tape 
wasting schedule.  That simply is not in the amanda view of how things work 
from the original conception well over a decade ago.

amanda, when left to her own devices, will figure out a schedule (provided 
your settings in amanda.conf are sane) that will backup a 50GB system to a 
4GB tape, using one tape per nightly run, every night of a 7 day dumpcycle, 
filling each tape to 95% of its capacity, and do it without ever hitting an 
EOT _if_ your data is fairly stable.  Admittedly that's a little extreme, but 
I have done it.

This does mean that it might take amanda a week or more to figure out a 
suitable schedule, but it should only be adjusted if amanda is falling 
farther and farther behind when looked at over a 2 or 3 dumpcycle period.

You cannot, and should not, ever figure on using (v)tape number-007 on a 
certain night of the week, again, amanda is managing the re-use of the tapes, 
and a sneeze sometime that requires you to do a catchup flush will advance 
that usage schedule by a day, and before you know it, the (v)tape named 
Daily-tuesday will be actually used on monday or earlier.

-- 
Cheers, Gene
"There are four boxes to be used in defense of liberty:
 soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
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