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

Rob,

Yep - you can drop a lot of arms on newer systems and still outperform a lot more older disks/arms - as you discovered.
I'd guess just a few 15k RPM SAS drives (139.5GB or 283GB) would outperform a flock of old 4 or 8GB drives.
Besides, what current/new system could you attach those to, and where would you get them from
- apart from a museum, garbage dump - or raiding Frankie ! ;-)

Also with the new 3rd generation SSD's available December 6 (387GB and 775GB) you're also getting to the point where you may be better off say with a new small sized box and 2 to 4 SSD's (mirrored) instead of spending the extra for additional expansion units to house a load of spinners (if you needed more more than the 8 spinners in the CEC).

Of course with a 15k RPM SAS 139.5GB spinner at US$498 and a 283GB at US$950, vs.
a 387GB SSD at US$3588 and 775GB SSD at US$6200 there's still a bit of a price spread
the savings from dropping additional expansion units need to cover. :-)
(One thing with the SSD though is you can order one 4-pack at a special price on a new system, so for example instead of the first 4 x 387GB SSD's costing US$14,352 you can get them for US$12,917).

Neil Palmer, Waterloo, Ontario, Canada

(This account not monitored for personal mail,
remove the last two letters before @ for that)

--------------------------------------------
On Tue, 10/22/13, rob@xxxxxxxxx <rob@xxxxxxxxx> wrote:

Subject: Re: Disk requirement (performance-wise) on a Power 7 replacing a System i 520
To: "Midrange Systems Technical Discussion" <midrange-l@xxxxxxxxxxxx>
Received: Tuesday, October 22, 2013, 3:01 PM

Should 70GB drives be used for stale
data?  These drives are so huge that
wouldn't one be better off just using them for non volatile
data and use a
bunch of 4 or 8gb drives instead for their more volatile
data?  This way
you get more arms?

Not a real question.  It's just something to put how
times are changing
into perspective.  With disks available in >800Gb
size, which is currently
22 times the size of Jeff's current drives (which is close
to the ratio
between 4 and 70GB drives), let's not assume that such
monsters are best
just utilized for stale non volatile data.

Just speaking as someone who once went from 42 arms down to
7 and got much
better performance.


Rob Berendt
--
IBM Certified System Administrator - IBM i 6.1
Group Dekko
Dept 1600
Mail to:  2505 Dekko Drive
          Garrett, IN 46738
Ship to:  Dock 108
          6928N 400E
          Kendallville, IN 46755
http://www.dekko.com

--