On Thursday 10 October 2002 17:18, John Koenig wrote:
>Related question....
>
>>A single amdump run if larger than a single tape can be placed on
>>multiple tapes if the runtapes parameter is > 1.
>
>I have a scenario with a changer wherein the runtapes is 1 however
>some days it does not manage to schedule the backups such that it
>uses only one tape...
>
>Are there some guidelines one can use to modify  parameters in
>amanda.conf such that the behavior of AMANDA changes enough to use
>one tape per run instead of one tape 70% of the time?
>
>Or should I post a representative history of my amdump summaries
> with the hope that someone can make specific suggestions, that
> way?

One thing you might consider is to break the largest pieces of the 
disklist up into smaller subdir lists.  This means you'll be using 
tar of course.  Amanda can then adjust her schedule a bit more 
fine-grained and avoid such situations.  I like to have it so that 
no one entry in the disklist exceeds, before compression, the size 
of a tape/2.

Another thing is to check and make sure the drives compression is 
turned off because if its on, then the true tape capacity is hidden 
from amanda and amanda may schedule more than will fit on a tape 
because of this.  Amanda counts bytes sent to the drive after any 
compression she might have called upon.  Software compression, 
properly applied, can beat the socks off the drives hardware 
compressor, like last night, I put 5059 megs of raw data on 1618 
megs worth of a 4 gig DDS2 tape, for a compression of 31.7%.  The 
drive couldn't touch that by about 900 megs if it was doing the 
compressing.

Some drives can make turning the compression off quite a party as 
they'll reset it each time they recognize the tape to whatever the 
tape was before.  You can beat that, but it takes a bit of 
tomfoolery from the cli to do it. Search back up this list for a 
week maybe 2 as I've repeated this proceedure description several 
times now.

-- 
Cheers, Gene
AMD K6-III@500mhz 320M
Athlon1600XP@1400mhz  512M
99.17% setiathome rank, not too shabby for a WV hillbilly

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