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Re: Disk requirement (performance-wise) on a Power 7 replacing a System i 520



fixed

Add to Roberto's comments that the 36G drives came in 10K RPM and 15K RPM flavors. You probably have 15K Units (FC #4326) but not for sure.

Remember that too few drives can really cripple your performance, despite vastly more CPW if you can't get to the data you're hosed!

Also remember the price of drives now is fabulously lower than those older drives when they were new! So I always recommend that you start with 8 drives in a RAID 5 with hot spare configuration.

One 'simple' thing to do is on your system do WRKDSKSTS. Wait 5 minutes and do F5. Then look at the % Busy column (far right.) Tell us what those numbers are. DO do this when the system is at it's busiest time so you get numbers that are reasonable.

If what you see is 40 and 50% or higher (not likely) then 8 arms will never be enough. If you're seeing 1s and 2s though then 8 will be fine.

One more thing. MEMORY. It's cheaper than ever, get a lot. It helps disk business a lot!

- Larry "DrFranken" Bolhuis

www.frankeni.com
www.iDevCloud.com
www.iInTheCloud.com

On 10/22/2013 1:08 PM, Roberto José Etcheverry Romero wrote:

16drives on a 520 means you have at least one 0595 and drives on both
the CEC (with it's sucky 40mb controller) and the 0595 (with a wide
range of controllers).
I would think that any controller at the p7 level would stomp the
ground with those. I'm not so sure on the disk arm side, i keep
reading that a bare min would be 6 arms...
To be able to compare properly you would need to get a rack config, or
at least list the disk controllers and which drives are hooked up to
which controller.
And check which controller would be on the power7 machine...

Best Regards,


On Tue, Oct 22, 2013 at 2:00 PM, Jeff Crosby <jlcrosby@xxxxxxxxxxxxxxxx> wrote:
All,

I've asked a BP for a quote on a Power 7 to replace our System i 520,
thinking that maybe the 3 year cost wouldn't be much more than the
maintenance alone on the System i. Haven't received the quote yet, so I
don't know if I'm delusional or not.

Anyway, the System i has 16 ~36gb drives at only 20% capacity. IOW we only
have 98gb data on the System i. Isn't the smallest drive available on the
Power 7 larger than that? At a minimum I would want 4 drives, raided, with
a 5th as a hot spare. Any way to tell the performance, disk-wise, of that
system as compared to our current system?

Thanks.

--
Jeff Crosby
VP Information Systems
UniPro FoodService/Dilgard
P.O. Box 13369
Ft. Wayne, IN 46868-3369
260-422-7531
www.dilgardfoods.com

The opinions expressed are my own and not necessarily the opinion of my
company. Unless I say so.
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