The new DASD and cache oriented controllers are very good performers. The
integrated 5727 controller has done very well for us on both DB2 based
systems and WAS/Domino setups. If at all possible, see if your business
partner can get some modeling done for you by Randy Watson's company
Midrange Performance Group (you can collect a period of current performance
data, easily send it to them, and they can send you 'What If' modeling back
against various blends of controller/disk setups. If your BP doesn't work
with MPG as a service, I think MPG also will sell you this service at a
pretty reasonable price (getting the right hardware spec'd with some expert
assurance based on hard data can be pretty valuable). The only thing i've
heard to really watch out for still is 3 drive RAID setups... that may have
been fixed in the last year or two, though.
"Jones, John
(US)"
<John.Jones@xxxxx To
l.com> "Midrange Systems Technical
Sent by: Discussion"
midrange-l-bounce <midrange-l@xxxxxxxxxxxx>
s@xxxxxxxxxxxx cc
Subject
04/24/2008 09:14 RE: small i & power systems (disk
AM performance)
Please respond to
Midrange Systems
Technical
Discussion
<midrange-l@midra
nge.com>
The 640 was SPD while the new machine will be PCIx or PCIe. SPD was at
least an order of magnitude slower than either PCI interface. 6501
controllers had no write cache; 6533s had 4MB.
And, each new generation of hard drives tends to have better performance
even at the same spindle speeds. Compare the 4th & 5th generation of
Seagate 15K drives. Note the huge differences in minimum & maximum
transfer rates and, more important for ASystemiSeries/400 shops, the
multi-user IOMeter (a.k.a. server) scores:
http://www.storagereview.com/php/benchmark/suite_v4.php?typeID=10&testbe
dID=4&osID=6&raidconfigID=1&numDrives=1&devID_0=321&devID_1=273&devCnt=2
Same manufacturer, spindle speed, and interface, but the 5th gen drive
trounces the 4th gen drive in every meaningful measure.
--
John A. Jones, CISSP
Sr. Analyst, Global Information Security
Jones Lang LaSalle, Inc.
Voice: +1.630-455.2787
FAX: +1.312.601.1782
Email: john.jones@xxxxxxxxxx
-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of rob@xxxxxxxxx
Sent: Wednesday, April 23, 2008 3:30 PM
To: Midrange Systems Technical Discussion
Subject: Re: small i & power systems (disk performance)
Somewhere in the archives I have an entry where I moved from 42 disk
arms
down to 7 and got a much better performance picture. I ran BPCS period
end's and everything to compare. And the machine with the 42 disk arms
had it's lan cable yanked and was pretty much dedicated to that testing
with most other tasks ended. The 'live' machine was not so constrained
yet still had great performance doing the same tests with active comm
and
users working away on it.
Today's newer drives and controllers will blow the doors off of those.
Rob Berendt
--
Group Dekko Services, LLC
Dept 01.073
Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com
Kirk Goins <kgoins@xxxxxxxxxxx>
Sent by: midrange-l-bounces@xxxxxxxxxxxx
04/23/2008 03:29 PM
Please respond to
Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
To
Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
cc
Subject
Re: small i & power systems (disk performance)
Keith Carpenter wrote:
System experts,
We are looking to move an old 640 with 72 8gb disks to a new low end
system. CPW should be no issue, but I'm concerned about disk IO
performance in these 520+/515/525 systems.
I had hoped to go with an 8 disk system (CEC only), but from what I've
read in the archives, you need an expansion box to be able to use a
better RAID controller. How much of an improvement would a 0595 and
something like a 5777 actually make over the integrated controller
(w/5727 cache) ?
Does the new power 520 offer anything better ? Is the integrated SAS
controller much of an improvement ? Can we put a better RAID directly
in the CEC ?
TIA,
Keith
You need to collect some basic performance data.. Mainly how many Disk
I/O per second you are doing now under your normal load conditions. The
8GB drives 'MIGHT' me 10K at best and the controllers may have 104MB
cache depending on the card. The SAS drives are 15K and according to IBM
are 10% to 15% faster than their SCSI counter parts.
According to PPT slide I have the internal raid controller can handle
1100 to 1400 I/O per second as long as individual drives do not exceed
110 I/O per second
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