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Need to optimize the execution time to mount tape dataset

 
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muthukumarit

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Joined: 27 Jun 2008
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Location: Bangalore

PostPosted: Sat Aug 02, 2008 1:01 pm    Post subject: Need to optimize the execution time to mount tape dataset
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There is a typical requirement in our application. We would like to optimize the timetaken by a job which mounts nearly 100 tape datasets and then copy the records in those datasets to a flat file using some key fields in the tape file. Currently its taking nearly 7 hours for execution. Can you please suggest some ways to optimize the execution time.
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Anuj Dhawan

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Joined: 22 Apr 2006
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Location: Mumbai, India

PostPosted: Sat Aug 02, 2008 1:43 pm    Post subject:
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Hi,

At my shop if I use 12-tapes in a single a JOB, my storage guy visti me with a n expression of icon_evil.gif & some "polite" wordings.. icon_smile.gif.

Quite strange for me to use 100-tape files in single job, however can think of two things-

- split the the JOB in some 'smaller' JOBs
- Try using virtual tape (not used ever, but 100 tapes, sorry brother, can't even experiment at my shop)
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dick scherrer

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Joined: 23 Nov 2006
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PostPosted: Sat Aug 02, 2008 7:19 pm    Post subject:
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Hello muthukumarit and welcome to the forums,

Does this copy job have many steps or is it one large step that concatenates the input for the copy?

Is there one output flat file or are there several?

Please post the jcl from 2 of the problem steps if there are more than 1, if only 1, please post that step - i may have an idea.

Are your tapes in a silo or are they manually mounted when the job is run? If the tapes are read from a silo, they should all be in the silo when the job begins. If they are manually mounted, they should all be staged to the tape handling area prior to starting the job. Running around to gather tapes to load into a silo or manually mount can waste a lot of time.

How long does it take to process one tape? How many records are on a tape? You need to determine if the time is spent waiting on tape mounts or if most of the elapsed time is actually processing data. If the process takes that long, looking at the code may be in order. Keep in mind that your process is processing a tape (mount and read the data) every 8 minutes or so.

Quote:
Try using virtual tape (not used ever, but 100 tapes, sorry brother, can't even experiment at my shop)
You have to use the media where the files are. . . V-Tape can be very handy, but not for files already existing on tape. . . Unless the organization is ready for a migration to virtual tape. I believe 100 tapes should not be confused with 100 tape drives. One of the processes i inherited reads an average of 6 tapes per month for up to 15 years of data (over 1000 tapes) but i keep it down to 4 physical drives.
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Anuj Dhawan

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PostPosted: Mon Aug 04, 2008 11:33 am    Post subject:
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Hi,
dick scherrer wrote:
I believe 100 tapes should not be confused with 100 tape drives.
Perhaps I would need little more explanation on this, idiot in me is not getting it fully..Please assist.
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dick scherrer

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PostPosted: Mon Aug 04, 2008 11:51 am    Post subject:
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Hi Anuj,

Think of tapes (volumes) as cd/dvd's and tape drives as cd/dvd players.

One is the media and the other is the hardware to read/write the media.

Using many volumes is not usually going to bring the operations or storage management people to your desk. Using many tape drives probably will icon_wink.gif
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Anuj Dhawan

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PostPosted: Mon Aug 04, 2008 12:01 pm    Post subject:
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Hi,
dick scherrer wrote:
Using many volumes is not usually going to bring the operations or storage management people to your desk. Using many tape drives probably will icon_wink.gif
Your frequencies are matching well with me today, thanks..I got it.. icon_smile.gif
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gcicchet

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Joined: 28 Jul 2006
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Location: Australia

PostPosted: Mon Aug 04, 2008 12:33 pm    Post subject:
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Hi Anuj,

you can see Dick works for a very rich employer, 100 tape drives wow icon_lol.gif


Gerry
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Anuj Dhawan

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PostPosted: Mon Aug 04, 2008 12:42 pm    Post subject:
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Yeah, in real when compared with mine ..phew..just 12..I feel inferior..ah..

-Ad
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dick scherrer

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PostPosted: Mon Aug 04, 2008 12:44 pm    Post subject: Reply to: Need to optimize the execution time to mount tape
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Would you believe over 2 million tape cartridges and over 60 silos?

This does not count the very large "inventory" of "virtual tapes". . .

d
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