DYNAPCT and U0083



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DYNAPCT and U0083

Postby josechu » Wed May 08, 2013 12:56 pm

Hi mates, i've some doubts about correct use of DYNAPCT parameter in DFSORT using dynamic SORTWK files.

DYNAPCT was set to 50%, and default DYNALLOC to 4 areas. One SORT step fail due to fault of space, only try to use 3 SORTWK areas, imposible to obtain space, finish with a U0083. I can expect in these case that DFSORT (V1R12) must increase the default number of 4 to 6, but isn't the reality. In these moments exist lots of available space in other disks, ¿any idea?

ICE000I 1 - CONTROL STATEMENTS FOR 5694-A01, Z/OS DFSORT V1R12 - 08:42 ON TUE APR 30, 2013 -
0 SORT FIELDS=(01,04,A,05,08,A,23,02,D,25,01,A),FORMAT=BI
ICE201I H RECORD TYPE IS F - DATA STARTS IN POSITION 1
ICE083A D RESOURCES WERE UNAVAILABLE FOR DYNAMIC ALLOCATION OF WORK DATA SETS (970C)
ICE753I 0 FWK=(0,0) SWK=(3,2516580) TWK=(0,0) RWK=(0,0) TOTAL=(3,2516580) BLK=53216
ICE248I 0 ATTEMPTED TO ALLOCATE 220044MB OF DISK WORK SPACE ON 4 WORK DATA SETS
ICE249I 0 SUCCESSFULLY ALLOCATED 127718MB OF DISK WORK SPACE ON 3 WORK DATA SETS
ICE751I 0 C5-K76982 C6-K90026 C7-K58148 C8-K67572 E4-K58148 C9-BASE E5-K80744 E6-K58148 C4-K58148 E7-K79990
ICE750I 0 DC 196129791267 TC 0 CS DSVVV KSZ 15 VSZ 15
ICE752I 0 FSZ=29303719 RC IGN=0 E AVG=6696 0 WSP=254853071 C DYN=2516580 53216
ICE052I 3 END OF DFSORT

Thanks, best regards

Josechu
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Re: DYNAPCT and U0083

 

Re: DYNAPCT and U0083

Postby enrico-sorichetti » Wed May 08, 2013 1:06 pm

ICE248I 0 ATTEMPTED TO ALLOCATE 220044MB OF DISK WORK SPACE ON 4 WORK DATA SETS
ICE249I 0 SUCCESSFULLY ALLOCATED 127718MB OF DISK WORK SPACE ON 3 WORK DATA SET


what other messages did You receive ?

In these moments exist lots of available space in other disks


that' s not what <allocation> believed, and in these cases it is the system opinion that counts !
( maybe the other disks are not in the <storage pool> used/needed )

did You care to read the manuals about the meaning of the message
ICE083A D RESOURCES WERE UNAVAILABLE FOR DYNAMIC ALLOCATION OF WORK DATA SETS (970C)


and of the 970c reason code ?
cheers
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Re: DYNAPCT and U0083

Postby josechu » Wed May 08, 2013 1:24 pm

HI Enrico, many thanks

It've lots of free disks in same pool, isn't the problem. Error 970C are obtained trying to allocate a file larger than VTOC maximum permitted... in these case SORT try to obtain total space needed in three SORTWK areas, but this quantity is greater than total available space in the tree disks, causing ABEND U0083 (970C)

First problem, SORT use one SORTWK area less than default (uses 3, defined 4), and second, why DYNAPCT don't actuate?, we can expect a increment of a 50% in the number of SORTWK dynamic files, from default 4 to 6. But don't run...

I can solve easy, obviously increasing the DYNALLOC in the step SORT, OPTION DYNALLOC=(,6) i.e., question is why DYNAPCT apparently don't actuate?

I've no more MSG's in output of job.

Thanks for your help

Josechu
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Re: DYNAPCT and U0083

Postby dbetten » Thu May 09, 2013 7:42 pm

Josechu,
When doing the initial sortwork allocation, DFSORT still only uses the number of devices specified in DYNALLOC parm and fails if that initial allocation attempt cannot be sufficiently satisfied. The DYNAPCT causes additional work data sets to be allocated with 0 primary space and only used if later on during the input phase, the initial work data sets run out of space. This can usually happen if the file size is larger than expected or we run into some situation like intermediate merge. So this is why you need to increase your DYNALLOC to spread your initial work space allocation across more data sets.
Dave Betten
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Re: DYNAPCT and U0083

Postby josechu » Thu May 09, 2013 7:51 pm

Many thanks Dave, this explain situation.

A curiosity, know you why are used (allways), at least one dynamic SORTWK file less than the number defined in DYNALLOC? In these case 4 allocated, 3 used. Obviously isn't a problem...
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Re: DYNAPCT and U0083

Postby BillyBoyo » Thu May 09, 2013 8:05 pm

I think if you show the sysout from a step where this occurs, it may help.
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Re: DYNAPCT and U0083

Postby dbetten » Thu May 09, 2013 8:25 pm

Josechu,
What happened was that DFSORT did manage to find 3 volumes with enough space, it just could not find a fourth. That's why the ICE248I message says it attempted to allocate about 214GB on 4 work data sets, meaning you needed at least 4 volumes that each had 54GB of free space. It looks to me like DFSORT didn't find any volumes with that much free space so it reduced the space allocation a bit and retried, and was able to find 3 volumes with at least 40GB free space but could not find a fourth so the sort failed. So it's not that DFSORT only used 3, it's that DFSORT could only find 3 with enough space. For a sort this large, I'd suggest you increase your DYNALLOC to something like SYSDA,16 which means the 214GB sortwork allocation would be spread across 16 work data sets of about 13GB each. I'd also make sure your DSA value is set to at least 200 to get optimal performance. The shipped default is DSA=64 but you can specify DSA=200 on your OPTION statement.
Dave Betten
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Re: DYNAPCT and U0083

Postby josechu » Thu May 09, 2013 9:49 pm

Thanks by explanation Dave.

Don't worry, I know very good SORT in assignation of dynamic SORTWK files, now we're sorting a bit more than one Petabyte in the group, 100% without statics DD SORTWK*

DSA is set to 256 in ICEPRM, DFSORT in some cases uses values different from 256 or zero. This is one of this cases.

Many thanks again
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Re: DYNAPCT and U0083

Postby dick scherrer » Thu May 09, 2013 10:12 pm

Hello,

One thought would be to run multiple smaller sorts and then MERGE the sorted data to get the final output.
Hope this helps,
d.sch.
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Re: DYNAPCT and U0083

Postby josechu » Fri May 10, 2013 12:18 pm

Hi Dick, many thanks for your interest

Yes, I agree, it's a useful technic very used in the group, mainly sorting files with a enormeous size. FIrst we divide the original file in N 'little' files using OUTFIL SPLIT, second, we sort individual files with same criteria, and in a final step, merge the files sorted.

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