Marc,

RAID 1 is faster but a little more "disc wasting" of course.

I'd like to recommend
LDEV 1         2 * 4.2   RAID 1          4.2 net
LDEV 2         2 * 4.2   RAID 1
LDEV 3         2 * 4.2   RAID 1
LDEV 4         2 * 4.2   RAID 1
LDEV 5         2 * 4.2   RAID 1
and so on (you have 20 disks ...)

Advantage: a lot more spindles on seperate devices - this helped us a lot when
we had disc bottlenecks on large HP-FL disks in the past - we moved to 2 GB SCSI
disks with Mirroring on Priv.Vol - and the looked fine.
The same expereince was made when we installed for test purposes a new LDEV 1 (2
* 2 GB RAID 1) on Model 10 - now the old HP-FL will become a bottlenecks ... so
that we're planning to replace with Model 10 as well.

Disadvantage, of course: you will loose some potential disk capacity ... (RAID
1)

I do not know how Model 20 will work with a hot spare but this is an option on
Model 10 as well ....

Just another idea,
Best regards, Andreas Schmidt, CSC





[log in to unmask] on 16/03/2000 07:17:47 PM

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cc:    (bcc: Andreas Schmidt/GIS/CSC)
Subject:  DISK perf info needed



We have a HP3000 969KS220 connected to an external Model 20 Disk Array.
We are looking for very precise performance informations and guidelines on
how to configure this config for best performance.
Actually we have this config:
SPA : Ldev 1 = 2* 4.2 disks in Raid1

SPB : Ldev 2 = 4*4.2 disks in Raid5
          Ldev 3 = 4*4.2 disks in Raid5

All good ideas are welcome.

Marc GOLDSTEIN
Groupe BATIGERE
METZ
FRANCE