I'm not talking about overall performance measures, just about which box to run TSM on. If you do a general performance measurment, of course the S/390 will win. However, normally a S/390 box don't only run ADSM/TSM. It probably runs applications, DB/2 and other business critical applications.
Therefore, as a storage administrator, when trying to get more power from S/390 in form of processors, memory, disk, TSM will always have a very low priority. Also, this request is normally something that has to go way up in the organisation for authorization.
Doing a processor upgrade on a S/390 will cost more than buying a UNIX box in the size of a 660. If you're afraid of performance on the UNIX box, you can go all the way up to using 680:s or 690:s. I dont know any installation today requiring this much power, but it is possible.
And, let's take a look at how S/390:s disk subsystems are configured. The ESS contains two UNIX boxes. Why not running Linux here? Probably because of the outstanding disk I/O performance from the UNIX boxes.
Generally, the S/390 will outperform a UNIX box, especially when running transaction intensive applications such as DB/2. However, then running disk I/O intensive applications, UNIX will outperform the S/390 almost every time.
But it still all about priority on the S/390...
-----------------------------------
Daniel Sparrman
Exist i Stockholm AB
Bergkällavägen 31D
192 79 SOLLENTUNA
Växel: 08 - 754 98 00
Mobil: 070 - 399 27 51
-----"ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU> wrote: -----
To: ADSM-L AT VM.MARIST DOT EDU
From: Doug Fuerst <doug AT BKASSOCIATES DOT NET>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
Date: 03/20/2002 10:11PM
Subject: Re: Benefits of moving to platform other than OS/390
I don't believe you are correct. 390 I/O rates are generally orders of
magnitude larger than UNIX as there is simply much more I/O being
performed. Personally, having experience on both, I find 390 much easier to
administer, and the security is much more robust. And I don't work for IBM
either. 390 processor utilization is a product of the workload, and
adjustable via tuning. If your ADSM environment was not being dispatched
properly, then either you had a mistuned 390 system or an undersized
processor, or both. 390 is indeed a transaction processor par excellence,
but is no slouch in the I/O area, but it is indeed "optimized" for this
environment, as DB2 and CICS would not transact very well if it was not.
UNIX may be better at interactive applications, but I don't think it is
better at I/O, transaction, or batch processing. And a 390 is infinitely
more scaleable, and now can run Linux anyway. And one 390 box can replace a
whole bunch of small UNIX servers.
Just my $.02
Doug
At 02:18 PM 3/20/2002 +0100, you wrote:
>Hi
>
>As far as I can see, moving do a UNIX platform only has positive effects
>such as:
>
>- Higher throughput. Normally, the S/390 guys only allows a minor amount of
>memory and processor utilization to be used by ADSM/TSM. This is not a
>problem when running a UNIX box.
>
>- The UNIX boxes normally have higher disk and tape I/O than a S/390
>system. Dont ask me why, but I have seen this in environments where TSM had
>existed on both UNIX and S/390.
>
>- Administration of a UNIX box is normally easier, and you don't have to
>have a IBM representative doing all the work.
>
>- S/390 is optimized for transactions, UNIX is optimized for
>disk/tape/network I/O.
>
>Best Regards
>
>Daniel Sparrman
snip>>>>>>>>>>>>>>>>>..
Doug Fuerst
Consultant
BK Associates
Brooklyn, NY
(718) 921-2620
doug AT bkassociates DOT net
