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Releasing DASD Space From Multi Volume Dataset

 
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manoopatil

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Joined: 07 Dec 2003
Posts: 56
Location: Montreal

PostPosted: Fri Jun 26, 2009 3:14 am    Post subject: Releasing DASD Space From Multi Volume Dataset
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Hi,

There are certain multi volume GDG files which are allocated with more than 1,500 cylinders. However only 10-15 cylinders are getting used. There is a RLSE parameter used while allocating space to these files. However being a multiple volume dataset, the space is not released using RLSE, neither I can use "FREE" command for it.

Can any one provide a work around so that the over allocated DASD space be released from a multi volume dataset.

Thank you
-Manohar
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expat

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Joined: 14 Mar 2007
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Location: Back in jolly old England

PostPosted: Fri Jun 26, 2009 3:21 pm    Post subject:
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Had you bothered to read the JCL manual you may have found this.
Quote:

RLSE (Partial Release)
Requests that space allocated to an output data set, but not used, is to be released when the data set is closed. This partial release parameter causes the close function to release unused space only if the data set is open to allow writing and the last operation was not a read or a POINT macro.

For a multi-volume sequential data set, only unused space on the current volume is released when the data set is closed; allocated space on any subsequent volume is not affected. This is also valid if the data set is GUARANTEED SPACE.

Please do not hesitate to post again if you need someone else to do your research for you icon_evil.gif

Are you using a guaranteed space STORCLAS? How is the space allocated - during or before the step that writes to the dataset?
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dick scherrer

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PostPosted: Fri Jun 26, 2009 8:51 pm    Post subject:
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Hello,

You might try an experiment with a smaller primary and a moderate secondary allocation. When the close happens, you would probably be "on the current volume" and not retain the extra space.
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manoopatil

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Joined: 07 Dec 2003
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Location: Montreal

PostPosted: Sat Jun 27, 2009 4:42 am    Post subject:
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Thanks Expat and Dick,

I will check on Storage Class, the way space is allocated, Possibility of allocating smaller primary...Will get back to you with details.

Thanks
-Manohar
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manoopatil

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Joined: 07 Dec 2003
Posts: 56
Location: Montreal

PostPosted: Wed Jul 01, 2009 2:53 am    Post subject:
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Hello Expat/Dick,

Guaranteed Space is NOT used on STORCLAS.

The space is first allocated to the GDG in following manner and in the subsequent step the data is written to this GDG version using the disposition as "SHR"

Allocation of Empty File:-
Code:
//CREATE  EXEC PGM=PDRFILES,REGION=1M
//OUTPRT1  DD  UNIT=SYSDA,DISP=(NEW,CATLG,CATLG),
//             SPACE=(TRK,(500,50),RLSE),VOL=(,,,10),
//             DSN=TELLPCB.KBSFHX00.PRINT.FILEL101(+1),
//             DCB=(DSORG=PS,RECFM=VBA,LRECL=5000)


Adding data to Empty file in Next Step
Code:
//STEP1 EXEC PGM=PDRSW000,REGION=0K,TIME=120
//SYSPRINT  DD SYSOUT=(,),OUTPUT=(*.ONLJCL)
//REPORT    DD SYSOUT=(,),OUTPUT=(*.ONLJCL)
//OUTPRT1   DD DSN=BELLPCB.CBSFHX00.PRINT.FILEL101(+1), 
                         DISP=SHR


I verified that one volume at my installation can hold more than 54,000 tracks. And the datasets in question has maximum allocation of 30,000 tracks. Hence I am gonna get it changed from Multivolume to Single Volume Datasets.

After the data is written to the Single Volume Dataset. I will use DMS Procedure to release the idle space on these files.

Any suggestion to this approach is welcome.

Thank you
Manohar
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manoopatil

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Joined: 07 Dec 2003
Posts: 56
Location: Montreal

PostPosted: Wed Jul 01, 2009 2:57 am    Post subject:
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Sample for the DMS PROC which can be used to release the idle space
from the Sequential Single Volume Datasets.

Code:
//JOBNAME JOB (acct,info),etc.
// EXEC DMS
SCAN REALVOLS
**************************************************************
* SELECT SEQUENTIAL, NON-EMPTY DATA SETS, ALLOCATED IN *
* TRACKS WITH SECONDARY SPACE ALLOCATION, THAT HAVE GREATER *
* THAN 25 PERCENT USED AND LESS THAN 50 PERCENT USED. *
* *
* RELEASE SPACE SO THAT SELECTED DATA SETS HAVE 75 PERCENT *
* USED SPACE, AND RESET THE SECONDARY SPACE. *
**************************************************************
SELECT CRITERIA=(PCTUSED,NE,0,AND,DSORG,EQ,PS,AND,
PCTUSED,GT,25,AND,PCTUSED,LT,50,AND,
ALLOTRKS,EQ,YES,AND,ALLOSEC,GE, ,
VOLUMES=WORK/,DSNAMES=USER./
RELEASE PCTUSED=75,PCTSECONDARY=25
**************************************************************
* SELECT PARTITIONED DATA SETS, THAT HAVE GREATER *
* THAN 50 PERCENT USED AND LESS THAN 90 PERCENT USED. *
* *
* RELEASE SPACE SO THAT SELECTED DATA SETS HAVE 95 PERCENT *
* USED SPACE, *
* *
* RESET THE SECONDARY SPACE FOR THE SELECTED PARTITIONED *
* DATA SETS AND CONVERT CYLINDERS TO TRACKS. *
**************************************************************
SELECT CRITERIA=(DSORG,EQ,PO,AND,
PCTUSED,GT,50,AND,PCTUSED,LT,90,AND,
ALLOCYLS,EQ,YES),
VOLUMES=MVS/,DSNAMES=TEST./
RELEASE PCTUSED=95,PCTSECONDARY=50,CONVERT
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dick scherrer

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Joined: 23 Nov 2006
Posts: 19270
Location: Inside the Matrix

PostPosted: Wed Jul 01, 2009 3:14 am    Post subject: Reply to: Releasing DASD Space From Multi Volume Dataset
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Hi Manohar,

Thanks for the updates icon_smile.gif

You will undoubtedly be someone's hero when they need this icon_wink.gif

d
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