Re: DASD performance curve graphs??

["Larry D. Bolhuis" <lbolhui@xxxxxxx>]

Terry,
<snip>
> The interesting thing about this thread to me is the activity issue.  Even
> on our 640 production box, at the busiest time of the day, supporting
> several hundred users, and OMS reporting 500,000+ database
> transactions per hour being mirrored, I've never seen the disc drives
> report more than 10% busy, and most of the time they're less than 5%.

  Well if you have a 640 you likely have a significant number of arms so you 
are likely proving the
point.

  It isn't generally the larger boxes with problems, since their larger 
databases typically require
enough arms just to store the thing, that performance of the arms is not a 
problem.  One additional
controller and some drives is not a big incremental hit for this size of 
machine. As an example my
two largest customers (a 640 2way and a 530 4way) have 68 and 76 drives 
respecively.  It's real
tough to push that many drives beyond 40%.

  What I see as the problem is the IBM BP 'doing a favor' for a site and 
selling them 17.5G drives
because they save on Drives, Controllers, and Racks. Problem is that you can 
get a LOT of power in
say an S20 4way. Put in RAID with 5 of those big drives and you have 70GB 
usable.  Sounds pretty
workable if you ignore the quidlines.

  Bottom line, don't let your BP 'do you a favor', When in doubt check it out.

-- 
Larry Bolhuis         |
Arbor Solutions, Inc  | Two rules to success in life:
(616) 451-2500        | 1. Never tell people everything you know.
lbolhui@ibm.net       |
+---
| This is the Midrange System Mailing List!
| To submit a new message, send your mail to MIDRANGE-L@midrange.com.
| To subscribe to this list send email to MIDRANGE-L-SUB@midrange.com.
| To unsubscribe from this list send email to MIDRANGE-L-UNSUB@midrange.com.
| Questions should be directed to the list owner/operator: david@midrange.com
+---