On Wednesday 27 September 2006 09:06, Jeff Portwine wrote:
>Hi everybody,
>
>Hoping somebody can clarify something about amanda for me.
>
>I have my backups set to run on a 3 day dump cycle with 6 tapes, running
> every evening except sunday night.    It seems to work fine, we change
> the tape each morning so over the course of a week (if I understand how
> amanda works right) we get two sets of full backups.    Sometimes we
> forget to change a tape, and most Saturdays we don't have anybody here
> to change the tape so on those days I thought that Amanda just backed up
> to the holding disk and then the next morning we could just change the
> tape, do an amflush, then change the tape again so that it would be
> ready for the next night.
>
>However, I've noticed that every time Amanda doesn't find a writeable
> tape (usually due to the tape not being changed that day) there is very
> little data written to the holding disk and the amflush is very very
> small.   The day after this, the dump is much larger than usual
> compensating for this.    When we change the tapes every day,  each tape
> is usually around 50% full.    On a day when we forget to change the
> tape or are unable to change the tape the amflush results in about 0.5%
> tape useage, and the day following the day we did the amflush tape
> useage is usually 85-90%.      Is this how it's supposed to behave?  
> How can I fix it to do a normal dump to the holding disk on days when
> either we can't change the tape or we forget to change the tape?
>
>Thanks for any explanation and/or tips.
>
>-Jeff

Look up the keyword "reserved" as its used in amanda.conf, the default if 
not specified there is 100%.  And the holding disk must, for this to work 
correctly, be larger than the tape.  I believe some combination of the 
above is silently effecting your backups.  I try to hold about 150% of a 
tapes size for holding space, with a reserve of 30% IIRC.

-- 
Cheers, Gene
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