> Does a level 9 everynight backup more data than an incremental everynight?

Yes.  Any data that changes prior to the first level 9 will be backed up
by all subsequent 9s.

Any data that changes prior to the first incremental will only be backed
up by the first, and not later ones.

> I do Level 1 through 4 on each consecutive Wednesday so the first Wednesday
> I do a level 1 and the next Wednesday I do a level 2 and the so on 
> with Level 9's
> each of the days in between.

Okay... (when do you do a full?)

> My uderstanding is that a level 9 will backup all data since the 
> previous lower level
> exclkuding level 9.

9 isn't a "lower level", so you don't have to exclude it.

> so my Saturday backup will backup all data since 
> Wednesday's level
> 1 for instance.

Correct.

> Does this mean that if a 1 gig file was changed on Thursday and then
> written to tape on Friday and if that file wasn't changed again on
> Saturday that on Sunday's backup it will still backup that file since
> it goes back to Wednesday's level 1??

Yes.

> If I did incrementals it wouldn't backup this file on Sunday and thus less
> data is written to that tapes?

Yes.  And more tapes are needed for restore.  Although by using
increasing levels on Wed, you're causing the same need.  At the end of
the month, your worst case for a restore is 

full, 1, 2, 3, 4, 9  (6 volumes) vs
full, 1, 2, 3, 4, incr, incr, incr, incr, incr, incr (11 volumes)

So it's a balancing act between how much data you store (and where it
goes) versus how much you trust tapes and how much you have to work to
do a restore.

-- 
Darren Dunham                                           ddunham AT taos DOT com
Senior Technical Consultant         TAOS            http://www.taos.com/
Got some Dr Pepper?                           San Francisco, CA bay area
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