On Tue, 24 Nov 2009 09:54:29 -0600, Mark Zelden <mark.zel...@zurichna.com> wrote:
>On Tue, 24 Nov 2009 07:15:24 -0800, Edward Jaffe ><edja...@phoenixsoftware.com> wrote: > >>Mark Zelden wrote: >>> A well known performance expert used to recommend that. But it wasn't >>> "NO" importance=1, it was that imp=1 should only be used or emergency >>> work and your "bread and butter" application(s). >>> >>> So I understand where the recommendation comes from. 10-15 years ago >>> I had a lot of consulting gigs doing WLM tuning (some were conversions >>> to WLM). I would say the majority of shops I went into way overused >IMP=1 and >>> at the same time underused IMP=5. >>> >>> So I happen to agree with that basic philosophy. There is very little >>> IMP=1 work here. WebSphere enclaves and the DB2 DDF period 1 >>> enclaves that support the same core applications. >>> >> >>Methinks this might be a hold-over from the "dark" days prior to the >>introduction of the CPU- and STORAGE-critical attributes. Importance >>ranking is what WLM uses to choose resource donors. And, real storage >>was let plentiful than it is today. So, people used to try to protect >>working sets for "loved ones" by assigning a relatively high importance. >>It seems a bit misguided now. But, that was the only relevant adjustment >>available to them (other than switching back to compatibility mode). >> > >Some of that is probably true. But from my experience at a lot of shops, >I think many of them just used IMP=1 for just about everything considered >"production online". All CICS regions, all DB2 subsystems, MQ, etc. Then >they would (misguidedly) try and use velocity to make some distinction >within that service class. Sorry, I wrote that wrong. Change "service class" to "importance level" or "workload" in the sentence above. >For example - when trying to translate the >compatibility mode model for putting a CICS "TOR above AOR", they would >make them both IMP=1 but use a higher velocity (and different service >class) for the TOR regions or do the same thing to "make DB2 higher than >CICS". > >I guess we need Rez to give us some details behind the post. > -- Mark Zelden Sr. Software and Systems Architect - z/OS Team Lead Zurich North America / Farmers Insurance Group - ZFUS G-ITO mailto:mark.zel...@zurichna.com z/OS Systems Programming expert at http://expertanswercenter.techtarget.com/ Mark's MVS Utilities: http://home.flash.net/~mzelden/mvsutil.html ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
