--On Thursday, October 23, 2003 15:53:23 +0200 Toralf Lund <toralf AT 
procaptura DOT com> wrote:

> Paul Bijnens wrote:
> 
>> Toralf Lund wrote:
>> 
>>> I'm thinking about using more than one tape, i.e. set "runtapes" 
>>> parameter to a value > 1, for my updated archival setup. Is there 
>>> anything special I need to keep in mind when doing this? Also, how do 
>>> I set up runspercycle in this case? Is it the total number of tapes 
>>> runspercycle * runtapes, or just runspercycle?
>> 
>> 
>> runspercycle does not need to be changed.  The "runtapes" means that
>> for each run up to that number of tapes may be used (note: not "must").
> 
>> You have to increase your tapecycle probably to cover the same 
>> dumpcycle(s), because you'll burn twice as much tapes for each run.
>> (well, "burn", hopefully not litteraly).
> 
> I'm still not sure I understand. If I have
> 
> runspercycle 2
> 
> and
> 
> runtapes 2
> 
> will amanda try to distribute the full dumps across 4 tapes, or just 2?

Well, technically your data could be spread over up to four tapes, but you are
only going to have one full backup of a single filesystem on one of the tapes
(assuming no promotions were made) and not on the others.
   Increasing runtapes just gives amanda more room to write a single day's
backups, but it is a maximum, so if all the scheduled backups fit on one
tape then it won't use the second one until the next run.

Frank 
 
> When I think about it, the first answer makes most sense, as the parameter 
> otherwise ought to have been called "tapespercycle".
  
> 
>> 
>> The parameter "taperalgo largestfit" will help to fill the first
>> tape(s) to 100%.  (New since amanda 2.4.3.)
> 
> I'm using that already.
> 
>> 
>> This works better when also using:
>> 
>> dumporder "SSSSSS"      # as many S's as you have dumpers
>> 
>> (or use "TTTTTT", which is a good approximation of SSSS, but optimises
>> the total runtime of your backups better; I use TTTTT).
>> 
>> For a complete explanation why this works better, see:
>> 
>> 
>> http://groups.yahoo.com/group/amanda-users/message/46327
> 
> This is very helpful indeed. Thanks.
> 
> I've been wondering how I might avoid having the largest image left on the 
> holding disk when the total size is only just larger than the tape (like you 
> say, taperalgo often doesn't help), but never noticed this parameter, or the 
> message you are
> referring to.
> 
> --
> - Toralf
> 
> 



-- 
Frank Smith                                      fsmith AT hoovers DOT com
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