Hi,
[EMAIL PROTECTED] schrieb:
>
> Hello,
>
> Does amanda need a minimum number of tapes to finish a dumpcycle of, say, 7
> days?
yes, runs-per-cycle tapes.
> My situation is as follows:
>
> There are two hosts to be backed up, one having a du of 7G and the other 3.5G.
> Day to day changes is less than 1% of the total du for each host. I have a
> single tape drive with 15G of uncompressed capacity (~30G compressed).
>
> To start, I plan on having a dumpcycle of 7 with a runcycle of 5. Can I set
> the tapecycle to 1 (or 2) and still have things backed up properly? The
> reason I have this restriction is because the machines in question are at a
> colocation facility, so changing tapes everyday is inconvenient at best.
two solutions posssible:
1.) get a changer with at least 6 slots.
2.) make a person in the colocation your human changer....
>
> Going by the simple math in the UB&R amanda chapter, I have:
>
> 11G / 7 = 1.6G
> 11G / 7 * 1(.01) = 0.02G
> 11G / 7 * 2(.01) = 0.03G
> 11G / 7 * 3(.01) = 0.05G
> 11G / 7 * 4(.01) = 0.07G
> 11G / 7 * 5(.01) = 0.08G
> 11G / 7 * 6(.01) = 0.10G
> = 2.0G
>
> I assume that the first run will do a complete level 0 dump, which will be
> 11G. So over a period of one week, 13G of tape would be used.
>
> Does my math make sense here?
no, because amanda will only put a single backup-run on one tape.
She does not append to tapes because of security reasons.
> What pitfalls should I expect by using only one tape per week? I've also read
> that the tapecyle should be ((Runs + 1) * #tapes), so in my case, this would be
> two tapes. So I suppose this means that I should at the least use 2 tapes per
> dumpcycle (which is one week)?
nope you should at least use 6 tapes.
> Also, by using one (or two) tapes means that amanda has to fit multiple images
> onto a single tape. Will this be a problem? How easy is it to recover from a
> tape with multiple images?
as amanda does not append to tapes you'll never have to recover from
such a tape...
> Thanks for helping a newbie,
> Antony
hope it helps to clearify the things a bit
Christoph
