[SAGE] NetApp--spindles vs. performance

["Guy B. Purcell" <guy@extragalactic.net>]

I'm posting this for a friend, whom I hope to be working with very soon 
:^)

He's specing out a NetApp filer (F810, I believe), and would like to 
know if anyone has any real experience with (or even well-educated 
guesses about) the performance gain of using 36 GB disks instead of 72 
GB disks.  The intended use will be about 50/50 for typical PC 
office-type files & Oracle DBs.

He needs to balance maximizing performance against minimizing cost.  
Using 36 GB disks costs more (need twice as many disks to achieve the 1 
TB storage goal), but that might be offset by significant performance 
gains from having twice as many spindles.  Are there rules of thumb for 
this sort of thing in general?  There must be some point of diminishing 
returns with shrinking disk size to increase spindle count (would that 
I had a system to experiment with!).  Thanks!

--
Guy
(guy@extragalactic.net)

Sysadmin for hire <http://www.extragalactic.net/guy/resume.html>