Eric, I don't think that this is unusual behavior.
My SWAG on this is that the less busy pages in DB2, and other addresses, are being paged out during overnight batch, and then paged in again the next day when online becomes active. At this point you end up with is a copy of unchanged pages in storage and still out on AUX. until the pages in CS are changed, or pages on AUX overwritten you have two copies which allow page out/in to operate by a "bit-flick" rather than actual page movement. The jump to 20% is probably you working set. There will probably be a small jump each following day as different pages are stolen, but not the order of magnitude you see on the first day. Caveat Emptor - it's still a SWAG. Ron > -----Original Message----- > From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On > Behalf Of Eric Bielefeld > Sent: Wednesday, November 12, 2008 8:06 AM > To: [email protected] > Subject: [IBM-MAIN] Page Dataset Growth and DB2 > > I have a situation with our page datasets that I fixed, at least for > the time being. I am curious though as to the behaviour of the page > datasets in relation to DB2. > > First, a little history of the problem. When I started here, one thing > I noticed was the page datasets were kind of small, and of different > sizes. We had 4 local page DS, the largest one being 1200 Cyl. This > past weekend, I made 4 full 3390 Mod 3 local page datasets, so I'm sure > the problems we had won't reoccur. > > I did notice, since I have been taking screen prints each day, that the > page dataset usage has been going up each day. On Monday, they > averaged 8% full according to the RMF Mon 2 Page/Swap Data Set Activity > report. This morning, they are almost 20% full. I assume by Friday > when I go home they will be at least 30% full, and probably limiting > block paging. > > My question is: is this normal DB2 behaviour? Or are we doing > something wrong. The guy who does some of the DB2 work thinks that DB2 > caching of data is causing this, and that the problem is agravated > because most of the batch jobs that run at night use REGION=0M to get > maximum region size. > > Another thing I noticed while looking at the RMF Mon 3 Storage Frames > Report, the Production and the Quality regions have almost doubled the > number of Aux Slots held in the page datasets. P went from 72K to > 128K, and Q went from 66K to 117K. This was in a period of time of one > day. > > The DB2 regions are started on Sunday, and left up all week until we > IPL Sunday morning. We still do weekly IPLs, just like my last full > time job at P&H! > > Anyway, is this behaviour normal? Are there certain things we might be > doing that we should be looking for? > > Thanks, > > Eric > > -- > Eric Bielefeld > Systems Programmer > Washington University > St Louis, Missouri > 314-935-3418 > > ---------------------------------------------------------------------- > 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 ---------------------------------------------------------------------- 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
