Ron,
SDB should be getting it right unless something is overriding the blksize.
Some samples of what you are getting would help.
Very General Rules:
- For any RECFM=VB/VBS you get 27998
- For anything else the blksize should be half track
- TRUNC(27998/LRECL,0)*LRECL
- DSORG PS and PO both get half track blocking
Ron
> -----Original Message-----
> From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On
> Behalf Of Ron MacRae
> Sent: Tuesday, 14 February 2006 7:06 PM
> To: [email protected]
> Subject: Re: DASD allocation guidelines
>
> Guys,
> Thanks for the replies. Sorry I should have been clearer on the
> question.
>
> The problem I have is that SDB is not producing the block sizes I, or more
> importantly my management, expect. Now it could be my understanding that
> is
> wrong or it could be that SDB is not getting it right, or, most likely in
> my opinion, hasn't enough information to make the 'correct' decision.
>
> We've been using SDB for some time. Some of the blocksizes it produces
> would be bad choices for a 'real' 3390 but we didn't care while under RVA
> because only the data was put onto real disk, we assumed this wastage of
> 3390 space was deliberate because there was no real correlation between
> 3390 space and RVA disk space. Now that we are on ESS/Shark, where I
> believe the whole volume is mapped to disk, it is more important to get
> the
> blocksize right, both for performance and capacity.
>
> I'm looking for guidelines to determine if SDB is getting it right.
>
> Regards, Ron MacRae
>
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