On Sun, Jul 30, 2006 at 11:58:54PM -0700, Liddle, Stuart wrote:
> Fine....believe what you want....but the numbers don't lie.  
> 
> If you ever try any testing of this you will see that  restores are
> significantly faster when you do them from non-multiplexed tapes.

There are 2 significant factors that affect the speed the restores:
1.  How many restores are you doing at the same time?  If it's more than
    1, then multiplexing will really hurt. 
2.  Are you doing single-file or multi-file restores?  If it's a
    single-file restore, then I don't believe that multiplexing makes a lot
    of difference (from what I've personally seen).  If you're doing a large
    multi-file restore, then multiplexing can cause a major performance hit.

I was talking to a Legato customer last week who said that he was
multiplexing 20-40 per tape and small restores could take 8+ hours.

As we always say, though, test and see what's acceptable in your
environment.  We all trade off backup times vs restore times and what's
acceptable for you may not be acceptable for me.

        .../Ed

-- 
Ed Wilts, Mounds View, MN, USA
mailto:ewilts at ewilts.org