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 -----
