DFSORT does not have a sort history function.
Have a nice day, Dave Betten DFSMS Performance Engineer IBM Corporation email: [email protected] 1-301-240-3809 DFSORT/MVSontheweb at http://www.ibm.com/storage/dfsort/ IBM Mainframe Discussion List <[email protected]> wrote on 04/18/2014 01:37:02 PM: > From: "Gibney, Dave" <[email protected]> > To: [email protected], > Date: 04/18/2014 01:37 PM > Subject: Re: SORT ando MEMLIMIT best practice > Sent by: IBM Mainframe Discussion List <[email protected]> > > I don't wish to start a SORT war. :) > Syncsort has the GDSM STC which, as I understand it, keeps a > history of sort performance/requirments and helps Syncsort choose > resource options. I actually have no idea how effective it is for usor others, > Does DFSORT have a similar sort history function? > > -----Original Message----- > > From: IBM Mainframe Discussion List [mailto:[email protected]] > > On Behalf Of David Betten > > Sent: Friday, April 18, 2014 10:31 AM > > To: [email protected] > > Subject: Re: SORT ando MEMLIMIT best practice > > > > DFSORT does look at available resources before it "grabs whatever it can". > > There are DFSORT installation defaults to control how much of theavailable > > storage DFSORT will use but I agree the shipped defaults can causeissues in > > some environments. We put a lot of guidance on these installation > defaults in > > our DFSORT Tuning Guide and in V2R1 we made some changes to try and be a > > bit less agressive in how we allocate available storage. > > > > > > Have a nice day, > > Dave Betten > > DFSMS Performance Engineer > > IBM Corporation > > email: [email protected] > > 1-301-240-3809 > > DFSORT/MVSontheweb at http://www.ibm.com/storage/dfsort/ > > > > IBM Mainframe Discussion List <[email protected]> wrote on > > 04/18/2014 01:15:51 PM: > > > > > From: Elardus Engelbrecht <[email protected]> > > > To: [email protected], > > > Date: 04/18/2014 01:16 PM > > > Subject: Re: SORT ando MEMLIMIT best practice Sent by: IBM Mainframe > > > Discussion List <[email protected]> > > > > > > Paul Gilmartin wrote: > > > > > > >R.S. wrote: > > > >> If you specify absolutely nothing about MEMLIMIT anywhere, the > > > system-provided default is 2G so obviously you can't go wrong with > > > that in SMFPRMxx. > > > > > > >Right. IBM's provided defaults are always optimal. > > > > > > Agreed. But, as John Gilmore said, IBM's defaults are 'minimal > > > troublesome' [ for 'most installations' <-- my own words ]. > > > > > > I usually find that these defaults are Ok and tailoring is reserved > > > for those strange needs. Oh, my MEMLIMIT is NOLIMIT after several > > > attempts to satisfy my DB2 needs and my z/OS Team handling of paging. > > > I'm not using USI exit much these days. > > > > > > >o Hmmm... I'd think that any parameterization resulting in > > > significant paging of I/O buffers is counterproductive. Is DFSORT > > > aware of this in its design, and does it attempt to tailor its WSS to > > > fit in real storage? > > > > > > Yes, I find that DFSORT looks what it can grab: memory, VIO, SORTWKxx > > > and SORTIN parameters for storage usage. Then DFSORT looks at what > > > size those SORT inputs are. At last, it tries to grab whatever it can > > > get to start sorting at all. > > > > > > >o OTOH, paging I/O is reported to be very good. And 64-bit virtual > > > is enough for most plausible data sets. How about eliminating SORTWKn > > > data sets and performing the entire sort in virtual storage? > > > But this approach must pay careful attention to LoR. > > > > > > Use SORTIN parameters to avoid SORTWKxx. Just don't code SORTWKnn in > > > your JCL DD statements. But, I agree, be careful. > > > > > > For myself, I find using SORTWKnn, large REGION and large SORTIN > > > parameters are 'better' for really big sort work. > > > > > > Groete / Greetings > > > Elardus Engelbrecht > > > > > > ---------------------------------------------------------------------- > > > For IBM-MAIN subscribe / signoff / archive access instructions, send > > > email to [email protected] with the message: INFO IBM-MAIN > > > > > > > ---------------------------------------------------------------------- > > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to > > [email protected] with the message: INFO IBM-MAIN > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to [email protected] with the message: INFO IBM-MAIN > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
