Ted, I would disagree with your point (2) in one case.
For a VSAM dataset with the allocation coming from IDCAMS DEFINE
parameters, the primary is remembered in the catalog listing. If the file is
defined in a non-guaranteed-space environment with more than one volume
specified, the allocation succeeds only if the primary amount can be found on
enough volumes. All volumes except the first one are placed in CANDIDATE
status, and the space is not allocated. During file load, when it attempts to
go to one of the candidate volumes, it goes after the primary amount on the
next candidate volume, and the job fails if it is no longer there.
As a note, we always defined these multi-volume VSAM files with zero
secondary so that they could not eat all the extra space on the volumes. It is
possible that this '0' secondary affects the behavior with the candidate
volumes.
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-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of
Ted MacNEIL
Sent: Friday, October 15, 2010 3:55 PM
To: [email protected]
Subject: Re: Space allocation question...
>I tried above allocation but I am getting just 3336 cylinders as initial
>allocation.
>What could be wrong here? Should the volumes be non-SMS?
>If they are SMS does it need some SMS rule to allocate primary space specified
>across each of the volumes?!
Space management 101:
1. The primary is satisfied in one extent only if there is a free extent that
large (or larger).
The primary must be satisfied within 5 extents, or the allocation fails.
2. The primary is never 'remembered'. So, if you go to a subsequent volume, the
secondary allocation is always used (and must, again, be satisfied within 5
extents.
The above are true whether or not SMS is involved.
-
I'm a SuperHero with neither powers, nor motivation!
Kimota!
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