Additional info,
I found out where the default allocation is coming from (CDS base
configuration). Apparently, when they setup the SMS default configuration,
they setup the default unit to be 3390 and the default bytes per track to be
56665 :
Default Management Class : Default Device Geometry :
Default Unit . . . . . . : 3390 Bytes/track . . . . . : 56665
Tracks/cylinder . . . : 15
The bytes per track is the same for a 3390 mod 3 and 9 (56,664) but is the
allocation tripled when a mod 9 is used?
On Wed, 16 Apr 2008 12:28:13 -0500, Gilbert Cardenas
<[EMAIL PROTECTED]> wrote:
>Hello everyone, I have an unknown that I have not been able to figure out or
>at least I don't know where to look.
>I have a user who is trying to define a vsam file using IDCAMS as follows:
>
>DEFINE CLUSTER -
> ( NAME(BLAH.BLAH.BLAH) -
> LINEAR -
> REUSE -
> CYL(30) -
> SHAREOPTIONS(3 3) ) -
> DATA -
> ( NAME(BLAH.BLAH.BLAH.DATA) -
> ) -
> CATALOG(BLAH)
>
>The problem is, when I look at the dataset (which is SMS managed) it usually
>ends up being around 3 times larger than what the user requested.
>
>Of course the first place I looked was in the dataclas that this dataset gets
>assigned and the only thing that the dataclas specifies is a volume count of
1.
>There are no overrides anywhere else for primary or secondary space.
>
>Looking at the Access Method Services documentation, it states that you
>should not use the TRACKS or CYLINDERS parameters. If you use them for an
>SMS-managed data set, space is allocated on the volumes selected by SMS
in
>units equivalent to the device default
>geometry.
>
>Could the reason that this dataset is being allocated larger than requested
>have to do with the fact that the sms volumes are mod 9 volumes?
>
>Btw, I tried allocating the dataset in Megabytes (30) and I got 43 cyl with 1
>extent. I don't know what the conversion of megabytes to cylinders is but
>this still doesn't seem right.
>
>Regards,
>Gil.
>
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