I'm with Ted on this one. We also started years ago with one or two DDF service classes, and they quickly became woefully inadequate. We tried a variety of configurations, from a 5-level priority system with multi-periods, to one or two with single periods. In our environment, the most efficient and most effective has been to code a HI/MED/LOW setup with three service classes, each with ONE and ONLY ONE service class period each, based on a percentile/time goal like "80% complete in 0.500 seconds" that very closely matched our CICS transaction goals in importance and %/t goal.
We found that as DDF transactions moved from period to period, their response times dropped dramatically. Why put it in HI if it's just going to end up LOW? Our customers screamed when the systems got busy, and their transactions started running longer, and began to traverse to LOW. So for us, HI means HI, end of story. We also found, in post processor reports, that multi-period DDF caused transactions that traversed all periods to use about 5% MORE service units than when they stayed in one period. We didn't have the head room to allow for this kind of inefficiency. Your mileage may vary. Try something based on your business goals. Monitor and tune from there. %/t goals are great in that they give you all the facts of what happened in black and white, and are easy to tune from. Best luck, Gary Diehl MVS Support "The glass is neither half full or half empty; the engineer who designed the glass simply allowed for a 100% increase in fluid storage." -----Original Message----- From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Ted MacNEIL <big snippage> 7. Monitor. Analyse. Tune. Rinse. Repeat. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
