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Space parameters for a KSDS file.

 
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rameshvs
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PostPosted: Tue Aug 21, 2007 12:42 am    Post subject: Space parameters for a KSDS file.
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Hi All,

I need to allocate a KSDS file with alternate index. Here are the specifics. I know the record length 150 which is fixed. The index is 16 byte long and alternate index is 10 bytes long.

Now we have a limitation that maximum size of VSAM can be 4GB.

We need to determine the space parameters for the VSAM file with optimum usage of the space as we might up allocating many such files.

Can anyone please help me how best this can be done and the calculation used for determing the same.

I have gone through which detail similar stuff for flat files but wanted to know about this for VSAM.

Thanx a lot in anticipation.
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CICS Guy

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PostPosted: Tue Aug 21, 2007 2:17 am    Post subject: Re: Space parameters for a KSDS file.
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rameshvs wrote:
We need to determine the space parameters for the VSAM file with optimum usage of the space as we might up allocating many such files.
Very short sighted, putting a person who has no idea of space requirements calculations in charge of calculating space requirements for a VSAM KSDS file and an AIX on that base cluster....
I would suggest, if you can come up with suitable interval and area sizes, that you just load the thing and see how much of the allocated spaces a set number of records occupy. Base cluster is easy, but index levels and total size is the goal.....
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ofer71

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PostPosted: Tue Aug 21, 2007 10:53 am    Post subject:
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I strongly recommend to read the relevant chapter in the fine manual.

O.
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expat

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PostPosted: Tue Aug 21, 2007 1:25 pm    Post subject:
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Is it a batch file, online file, both ?
How many records will there be ?
Going to do any inserts ?

How many duplicate AIX keys do you expect to be present, if any ?

The limit on 4GB VSAM was resolved with SMS version 1.3, about 10 years ago
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rameshvs
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PostPosted: Tue Aug 21, 2007 6:10 pm    Post subject:
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Thanks for all the responses.

Expat, this is a batch process. We are expecting records upto half a billion or so thats why we night end up creating more files. We will have only one AIX and there will not be any duplicates.

The 4 GB limit for VSAM I/O with C,C++ is present until z/OS V1.7 looks like got resolved with 1.8 but we are still using 1.7.
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