Thanks for all your response. You're all been very helpful. I have another
question. If I enabled the guaranteed space with a big unit count, will it
prevent the E37 abend? I somehow noticed that using the SDR allocation if
one of the striped volume can't extend it will abend E37. 

David, how did you code your ACS routine to select different storage
classes? Can you send me a sample?  TIA.

Regards,
Jason  

-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf
Of Ron Hawkins
Sent: Tuesday, April 08, 2008 12:55 AM
To: [email protected]
Subject: Re: Sequential Data Striping

David,

You can allocate the stripe chunks using a Guarenteed Space STORCLAS and
UNIT COUNT specified in the DTACLAS or JCL. In this case it will always give
you stripes equal to the UNIT COUNT with space for each chunk equal to the
Primary space requested. My experience is that this is more commonly used in
shops that have leveraged striping in a large way.

For Data Rate allocations SMS will not fail the allocation if Primary Space
cannot be satisfied. It will try again requesting fewer, larger datasets.
You always get the space you want, but not necessarily the throughput (then
again, you are asking in multiples of 4MB/sec).

Ron

> -----Original Message-----
> From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On
> Behalf Of David Andrews
> Sent: Monday, April 07, 2008 9:09 AM
> To: [email protected]
> Subject: Re: [IBM-MAIN] Sequential Data Striping
> 
> On Mon, 2008-04-07 at 08:31 -0700, Ron Hawkins wrote:
> > If you are using data rate to allocate your stripes
> 
> Isn't that the *only* way to control striping?  My notes say you get
> one
> stripe for every 4MB/sec you specify in Sustained Data Rate.
> 
> (I have STRIPED2, STRIPED4 and STRIPED8 storage classes, with
> appropriate SDR values.  These are selected from my SC ACS routine
> based
> on the dataset's &SIZE.  Kind of a kluge, but I wanted large datasets
> to
> be striped in varying degrees, FSVO "large".)
> 
> > you don't always get the number of stripes you requested.
> 
> I haven't seen this, but I have plenty of space.  Why does this happen?
> 
> --
> David Andrews
> A. Duda and Sons, Inc.
> [EMAIL PROTECTED]
> 
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