I am not sure how valid it is anymore (it was more than 10 years ago). We did it after the initial implementation... the fragmentation was messing with the large data set allocations. With Large and extended format.. it may not be an issue. But I would keep it in mind if things start to get "weird". IBM never recommended it .. but it straightened things out at the time.
Rob Schramm Senior Systems Consultant Imperium Group On Thu, Jul 5, 2012 at 12:56 PM, Ron Hawkins <ronjhawk...@sbcglobal.net>wrote: > Rob, > > I have seen the small and large dataset concept discussed since the early > days of DFSMS. To tell the truth I have never seen the benefit of doing > this. > > It has been suggested that it helps reduce allocation failures by reducing > fragmentation, but having always worked in shops with ACC/SRS or similar I > was pretty aggressive with the rules and did not have a problem even when I > ran development STORGRUPs up to 5% free space. And I never defragged. > > If fragmentation is the reason for sized based pools, then I wonder if the > practice is still necessary. DFSMS has implemented some elements of ACC/SRS > to reduce allocation problems, and if you are using 3390-A with Cylinder > allocation areas you have a natural separation of small and large datasets > within the volume. > > I would say do not implement size related pools, but rather make sure you > make best use of allocation recovery in DFSMSdfp, ACC/SRS, PRO-SMS, or > whatever ISV software you have as part of your implementation. > > Ron > > > -----Original Message----- > > From: IBM Mainframe Discussion List [mailto:IBM-MAIN@LISTSERV.UA.EDU] > > On Behalf Of Rob Schramm > > Sent: Thursday, July 05, 2012 8:01 AM > > To: IBM-MAIN@LISTSERV.UA.EDU > > Subject: Re: [IBM-MAIN] Converting to SMS for the first time > > > > You may want to consider the use of a couple size-related pools. During > one > > analysis ... something like 80% of the data sets were below 5 tracks. > > > > > > Rob Schramm > > Senior Systems Consultant > > Imperium Group > > > > > > > > On Thu, Jul 5, 2012 at 10:52 AM, Elardus Engelbrecht < > > elardus.engelbre...@sita.co.za> wrote: > > > > > Ron Hawkins wrote: > > > > > > >I would urge you to consider vertical pooling rather than horizontal > > > pooling. > > > ... > > > > My key point is to go horizontal, and avoid vertical pooling. > > > > > > Vertical against horizontal? Perhaps I missed something in your post, > > > but in my very humble opinion, I think both sentences are not speaking > > > the same tongue.... > > > > > > Of course, I'm pretty sure I'm as usual wrong. Please correct me if > > > needed ... > > > > > > Many thanks and have a terrific day! > > > > > > Groete / Greetings > > > Elardus Engelbrecht > > > > > > ---------------------------------------------------------------------- > > > For IBM-MAIN subscribe / signoff / archive access instructions, send > > > email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > > > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, send > email > to > > lists...@listserv.ua.edu with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@listserv.ua.edu with the message: INFO IBM-MAIN
