Datasets report which are NOT releasing unused space



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Datasets report which are NOT releasing unused space

Postby prasad029 » Mon Sep 12, 2016 3:00 pm

Hi Friends,

I have a task to generate a Dataset report which have not released the unused space.
Recently we have seen some datasets which are though coded with RLSE parm, doesn't release the unused space which surged the storage usage.
Now, client want to see the list of DS which have not released the unused space, please suggest.
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Re: Datasets report which are NOT releasing unused space

 

Re: Datasets report which are NOT releasing unused space

Postby Robert Sample » Mon Sep 12, 2016 7:09 pm

The JCL Reference manual for the RLSE sub-parameter has a long list of specifications when it will or won't work. The manual also says
You can release space in the following additional ways other than by deleting the data set:

Partial release option in the management class
DFSMShsm space management cycle
PARTREL macro issued by an authorized program.

As far as finding the data sets, you could use DCOLLECT. You might also be able to generate a list using ISMF, if the data sets are under SMS control.
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Re: Datasets report which are NOT releasing unused space

Postby prasad029 » Mon Sep 12, 2016 7:51 pm

Thank you, Bob.
The DS are SMS managed. Which parameters under ""DATA SET SELECTION ENTRY PANEL" do you think can be used to get the list through ISMF. I am confused here as my list should be only the one's which have not released the space.
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Re: Datasets report which are NOT releasing unused space

Postby Robert Sample » Mon Sep 12, 2016 8:23 pm

my list should be only the one's which have not released the space.
You cannot know this -- period. If a data set releases space, then a later execution of a program causes the data set to allocate secondary extents, you don't know that the original request released space. All you know is that the data set has multiple extents and may (or may not) have some free space.

You should be working with your site support group and the storage management group specifically on your request; we don't work at your site and hence we have no idea of the specifics, unlike your site support group. ISMF allows you to specify filter criteria on a data set list by using PF8 after entering the initial screen of data; these filter criteria include % used. You need to use the VTOC data instead of the catalog, enter the HLQ (assuming all the data sets are under a single HLQ) and enter the storage group name on the initial screen.

And, by the way, it is considered rude not to use names are provided by the responders. I am Robert, not Bob -- I have never been called "Bob".
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Re: Datasets report which are NOT releasing unused space

Postby willy jensen » Tue Sep 13, 2016 12:37 pm

Well, sort-of possible. The VTOC program found at CBTTAPE.ORG file 112 can show percentage of used space for datasets on one or more disks. So if you know your dataset names you could scan the report for datasets where the used percentage is lower than expected. Depending on the dataset format.
I'm sure that other utilities can provide similar info, I just find the VTOC program very handy.
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