John,
You never, ever want to us RAID 5 on MPE, with any of the HP products.
The performance is awful. I remember a 3000 user who was an early
adopter of the 12H AutoRAID device. He (effectively) put everything
into RAID 5 and ended up with 1200ms service times. Service times
should be 12ms or less so he had a two-orders-of-magnitude problem.
Mirroring (RAID 1) is the best way to go with the Model 20's, especially
with Amisys. Some years ago Kevin Cooper of HP proved that Amisys is a
highly spindle-sensitive application and that when the individual drives
exceeded 2 gb performance began to degrade.
The bottom line: Use RAID 1 where ever possible. And, NEVER use RAID 5
when using HP's disk solutions.
Bill (not one "It depends" in the whole post!) Lancaster
-----Original Message-----
From: HP-3000 Systems Discussion [mailto:[log in to unmask]] On
Behalf Of John Bawden
Sent: Wednesday, March 09, 2005 6:50 AM
To: [log in to unmask]
Subject: [HP3000-L] Model 20 disc array
I'm starting project to move 48 4 & 9 Gb OLD drives to
model 20 arrays using 18GB drives. Can aynone who has
BTDT provide some advice on the pros and cons of using
raid 1 vs. raid 5? The current system is very much I/O
bound and I'm hoping to improve on that but want to
make sure I don't make the situation worse. I have
three volume sets with the system and Netbase on the
system volume, the 3rd party utilties such as
Powerhouse, Suprtool, etc. on another volume set and
then the Amisys account on the rest of the drives (43
of them. Any comments, advice, gotchas, etc. would be
greatly appreciated.
John Bawden
QualChoice
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