One of the upcoming benefits of the i is a PTF that will help "balance" the I/O on the system with disproportionate storage. I spoke with one of
their technical people and sometime this fall they're releasing a PTF that will help utilize SSD's. So you could put a couple of those large format
drives in the system and tie it to a couple of mirrored SSD's (or more) and outperform more "arms" because the system will now do dynamic balancing
that used to require you to run a STRASPBAL *USAGE. The system will now do it for you in i6.1 and POWER6. So you could compress some slower SAN
storage and tie it to faster internal storage and a couple of SSD's and the system would scream. Kind of dynamically doing what any good admin would
do for his *nix system with separate file systems and volumes. Now you can just have one big ASP and do the same automagically on the i.
Bill Epperson Jr.
Systems Communications Analyst
Memorial Health System
(719) 365-8831
rob@xxxxxxxxx
Sent by: midrange-l-bounces@xxxxxxxxxxxx To
Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
cc
09/28/2009 06:49 AM
Subject
Re: can POWER6 IBM i or System i run on non-IBM disk drives?
Please respond to
Midrange Systems Technical Discussion
<midrange-l@xxxxxxxxxxxx>
Larry,
All great points, but I have to ask some questions anyway...
What's the smallest drive you ever had to rebuild a raid set on in an i or
it's predecessors? How long did it take? If you take a 140gb, divided by
the size of this smaller drive, and multiply the time it took to rebuild
this smaller drive would you get the time it took to rebuild the 140? Or
have they drastically changed the speeds of the newer drives to bring down
the time? Do you think that if IBM came out with a 1TB drive raid time
would be a direct multiple of the time of the 140?
70GB are off the market, aren't they? And we found new 140's for about
the same price for the 70's. We ended up buying the same number of 140's
as we would if they were 70's. (And the system is only 35% full.) I
wonder if 1TB's were the same price as 140's if they would still buy the
same number. (I'm having a feeling of deja vu on this paragraph. Didn't
we discuss this in the last year or so?) I can see some people gagging at
the thought of buying new disk when they are only 5% full though.
Rob Berendt
--
Group Dekko Services, LLC
Dept 01.073
Dock 108
6928N 400E
Kendallville, IN 46755
http://www.dekko.com
From:
Larry Bolhuis <midrange@xxxxxxxxxxxx>
To:
Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
Date:
09/27/2009 11:22 PM
Subject:
Re: can POWER6 IBM i or System i run on non-IBM disk drives?
Sent by:
midrange-l-bounces@xxxxxxxxxxxx
Gadzooks is this guy speaking from a point of ignorance....
As has already been mentioned they are not the same and won't work
anyway, sector size, firmware, etc etc.
*IF* you got them to work then you would still have to deal with the
following issues:
1) Their MTBF is a mere fraction of drives designed and built for use in
servers that pound drives 24x7.
2) Their sustained throughput isn't as good as drives designed for the
purpose.
3) Consider protection. It takes roughly 3 hours to build or rebuilt a
RAID set on 140GB drives. Extend that to 1TB drives and you get about 21
hours! So WHEN (not IF, WHEN) one of those monster 1TB drives fails you
get a minimum of 21 hours of time with no protection and that's AFTER
the replacement drive is installed.
4) Consider that there have been multiple firmware issues with these
huge drives where they get 'bricked' and your data is gone.
5) Nearly every system I work on these days has plenty of disk capacity,
it's ARM count that's hurting, 1TB drives surely won't help that in any
way at all.
Even if you could you do NOT want these drives in your i.
- Larry
elehti@xxxxxxxxxxxxxxxxxx wrote:
Our network admin (a LINUX/PHP/open source/anti-IBM type of guy) says,
"If you need additional disk drives for your POWER6 IBM I machine, you
don't need to buy expensive disk drives from IBM.
Just buy some cheap 1-terrabyte Western Digital drives from Egghead,
etc. Their drives will work just fine."
Uh, I think that other drives would not work in this machine.
Your thoughts?
I don't know why I let his outlandish comments get under my skin.
Now I will post a question to IBM tech support and have them
verify/contradict his claim.
Then maybe I will be able to sleep undisturbed.
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