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Elapsed time while backing up VSAM file

 
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raghavmcs

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Joined: 14 Jul 2005
Posts: 105

PostPosted: Fri Jul 03, 2009 11:55 pm    Post subject: Elapsed time while backing up VSAM file
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Dear Experts,

Our shop is running one of the VSAM file backup job in the primary window(This is time) where we do all critical and important process.This job belongs to one of the critical gold application.

During this time the job A is used to backup VSAM file B on tape using ADDRSU utility.
There are around 83922000 records in this VSAM file and I do see the CPU and elapsed time as as follows

CPU time Elapsed time

.40 15.24

This is another statistics for another date
.50 28.30

The file is being backed up with the following paramaters

PARALLEL
DUMP DATASET
(INCLUDE(A))
OUTDD(BKUP1)
ALLDATA(*) ALLEXCP TOL(ENQF) SHR SPHERE

I just wanted to have your expert advise for if there could an scope of improvement for minimizing the lapsed time...
Thanks
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dbzTHEdinosauer

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Joined: 20 Oct 2006
Posts: 6966
Location: porcelain throne

PostPosted: Sat Jul 04, 2009 2:15 am    Post subject:
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yeah, stop running all that other stuff while this job is running,
then the elapsed time will be reduced.
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Robert Sample

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Joined: 06 Jun 2008
Posts: 7932
Location: Bellevue, IA

PostPosted: Sat Jul 04, 2009 3:04 am    Post subject:
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From the DF/SMS Storage Administration Reference manual:
Quote:
OPTIMIZE specifies the number of tracks to be read at a time, as follows:

* If n is 1, DFSMSdss reads one track at a time.
* If n is 2, DFSMSdss reads two tracks at a time.
* If n is 3, DFSMSdss reads five tracks at a time.
* If n is 4, DFSMSdss reads one cylinder at a time.
The default is OPT(1). Add OPT(4) after TOL(ENQF) which usually will speed up the dump.

However, as Dick said, an unknown amount of the elapsed time is due to the other work in the system and you're not going to be able to reduce elapsed time by much as long as your dump is having to compete with everything else.
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expat

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Joined: 14 Mar 2007
Posts: 8593
Location: Back in jolly old England

PostPosted: Sat Jul 04, 2009 2:53 pm    Post subject:
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f you have FAVER installed in your shop use that - much much better than DFdss.

IDCAMS EXPORT may also be faster.

Also consider using your SORT product to produce a backup of the file, and see if that makes a difference.
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