Tom,
If all goes well you will have at least one level 0 of each
partition during the dumpcycle.
With only a single dumpcycle of tapes in the tape pool you may
find that you lose your only level 0 if there are any problems,
ie: bad physical tape, need to do flushes, dirty drive...
How many more tapes you 'should' have depends on a lot of factors,
capacity, failure rate, available funds, cost of failure (politically
as well as economically).
----- Forwarded message from Tom Brown -----
so if i have say...
1 run per night on each weekday
10 tapes in rotation
what should the tapecycle be to eliminate this?
thanks
> Tom,
>
> You run the risk of overwriting your only level 0 of any particular
> parition. We have 2x dumpcycles of physical tapes for most of our
> amanda servers here.
>
> > > > tapecycle 20 tapes:
> > > > number of tapes to use per dumpcycle of 2 weeks. 10 tapes X 2
dumpcycles
> > =
> > > > 20 tapes.
> > >
> > > Yes, but you really should have an extra tape or two in there to
lessen
> > > the chance of a failed backup overwriting your last full backup. You
> > > should really consider doubling that number so you always have two
copies
> > > in case one should error on a restore (in which case you would lose
your
> > > newest data but you could at least still recover older files.).
> >
> > really? in my case i allways have tapecycle as dumpcycle*runspercycle
> >
> > is that bad?
> >
> > e.g ...
> >
> > dumpcycle 1 weeks # the number of days in the normal dump cycle
> > runspercycle 5 # the number of amdump runs in dumpcycle days
> > # (4 weeks * 5 amdump runs per week -- just
> > weekdays)
> > tapecycle 5 tapes # the number of tapes in rotation
> >
> > or another config....
> >
> > dumpcycle 2 weeks # the number of days in the normal dump cycle
> > runspercycle 10 # the number of amdump runs in dumpcycle days
> > # (4 weeks * 5 amdump runs per week -- just
> > weekdays)
> > tapecycle 10 tapes # the number of tapes in rotation
> >
> >
>
>
----- End of forwarded message from Tom Brown -----
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