--On Tuesday, May 17, 2005 14:16:38 -0400 John Young <j.e.young AT LARC.NASA 
DOT GOV> wrote:

> Folks,
> 
>    If you are using vtapes on a RAID for your backup
> media, is there any point to also using a holding disk?
> I can easily understand the use of a holding disk if
> you are using real tapes but am not sure what it buys
> you if you are using vtapes.  Any comments?

I would suspect it depends on where your performance
bottleneck is.  Without a holdingdisk amanda can only
do one DLE at a time, serializing all yourbackups.  With
a holdingdisk, several dumps can be run in parallel.
If your holdingdisk is on the same filesystem as your vtapes,
then I could see how disk contention might become an
issue, but if you have slow clients or slow links then that
might be outweighed by the loss from serialization.
   The holdingdisk also gives your backups some protection
from vtape failures (i.e. no space, bad changer logic, etc.).

Frank
> 
>                                               JY
> ------------------------------------------------------------
> John E. Young                             B1148/R202
> Analytical Services and Materials, Inc.     (757) 864-8659



-- 
Frank Smith                                      fsmith AT hoovers DOT com
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