Column 46 in ISMF option 4 (Data Class) allows you to create a DATACLAS that
overrides the SPACE values in the JCL. You can either change their DATACLAS or
change the DATACLAS they are assigned, no? Is that what you need?
OVERRIDE The OVERRIDE SPACE column 46 shows whether or not the data
SPACE class space attributes will override the space attributes
--(46)-- from other sources like JCL.
YES
Possible values:
YES Data class attributes will override others
NO Data class attributes can be overridden
??? Error obtaining data
-----Original Message-----
From: IBM Mainframe Discussion List <[email protected]> On Behalf Of
Jousma, David
Sent: Monday, April 7, 2025 2:48 PM
To: [email protected]
Subject: Re: Migrating Storage pools to EAV
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I think the point of my question wasn't worded clearly. The problem is poor
allocation coding over the years where coded primary and secondary allocations
are NO WHERE NEAR what is really needed. But because we have 100's of volumes
in the pool, and a dataclass that allows 59 volume multi-volume dataset, the
problem is masked because the dataset can get 123 extents on each of the 59
volumes. With a 20-1 reduction in volumes in the pool(1TB EAV's replacing 20
mod-54's), there might not be 59 volumes in the pool, and that dataset will now
take an x-37 abend that we will take the heat for.
That is what I am trying to avoid. Seems like my only option is to reduce the
size of the EAV so that there are more volumes, or make the developers fix
their JCL allocations. I was hoping for the pixie dust to work around the
latter, but I don't think there is anything. It would be nice if (here is the
pixie dust), that on dataset extent processing, if some number of x space is
requested, but is below some threshold percentage of the current file size, or
less than some site customizable minimal trk/cylinder quantity that it would
get overridden to something larger.
Dave Jousma
Vice President | Director, Technology Engineering
>
> -----Original Message-----
> From: IBM Mainframe Discussion List [email protected] On Behalf
> Of Jousma, David
>
> Sent: Friday, April 4, 2025 9:21 AM
> To: [email protected]
> Subject: Migrating Storage pools to EAV
>
> CAUTION: This email originated from outside of the Texas Comptroller's email
> system.
> DO NOT click links or open attachments unless you expect them from the sender
> and know the content is safe.
>
> So, we are finally biting the bullet and making 1TB EAV volumes our standard
> for UCB relief, etc. One "habit" my Storage team over the years had done to
> mask poor dataset allocations was to make the mainly used DATACLAS
> multi-volume, with a max of 59 volumes. It was before my time, but I'm 99%
> sure that was done to avoid x37 abends for max extents. Now that we are going
> to EAV's, we'll be clearing off the mod-54's and DISNEW them. And with a 20-1
> reduction in physical volumes, there will likely be pools that had say 100
> volumes, that could end up with just 5 EAV's.
>
> I'm not a storage guy by craft, so am wondering if there is any magic dust to
> help with this other than making the owners of the poorly allocated files
> make adjustments to their allocations?
>
> Dave Jousma
> Vice President | Director, Technology Engineering
>
>
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