There used to be a legitimate performance reason for doing this 20 years
ago when accesses to the index alone on a hot VSAM file could saturate a
single real 3380/3390 drive. With today's emulated DASD, DASD Subsystem
cache several orders of magnitude larger, multiple PAV accesses to a
logical drive, and faster physical drives, all the motivations for doing
this in the past have essentially vanished. Even if DASD subsystems
with PAV support might cost more, it is still cheaper than personnel
costs associated with micro-managing DASD file placement (and the
additional performance costs when that micro-management is done less
than perfectly).
Joel C Ewing
On 06/20/2012 11:12 AM, O'Brien, David W. (NIH/CIT) [C] wrote:
George,
It might help to know what you're trying to accomplish by doing this.
Given the size of today's disks, there is no guarantee that placing the Data
and Index on separate Logical volumes will in turn place them on separate
physical volumes.
Regards,
Dave O'Brien
-----Original Message-----
From: George Rodriguez [mailto:george.rodrig...@palmbeachschools.org]
Sent: Wednesday, June 20, 2012 11:34 AM
To: IBM-MAIN@listserv.ua.edu
Subject: Splitting the DATA and INDEX Components of Extended Addressing Dataset
I'm hoping that someone can help me out here...
Is there a way through the ACS routines to allocate the DATA component on one
disk volume and the INDEX on another and are you willing to share the code or
knowledge?
Thanks in Advance!
*
*
*George Rodriguez*
*Specialist II - IT Solutions*
*Application Support / Quality Assurance* *PX - 47652*
*(561) 357-7652 (office)*
*(561) 707-3496 (mobile)*
*School District of Palm Beach County*
*3348 Forest Hill Blvd.*
*Room B-251*
*West Palm Beach, FL. 33406-5869*
...
--
Joel C. Ewing, Bentonville, AR jcew...@acm.org
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