so you are not constrained yet. When a page is needed below the line, if there are no pages on the "below the line available list", vm will find a page from below the 2gb line to page out. It will NOT go to central above the line, even if there are gobs of available storage above the line. After the page is moved out, then CP will move the needed page below the line. At some point, this rate will get excessive, or cp can't find a free page below the line to move, or expanded fills up. THEN things get bad.
DIAG 44 is caused by your MP linux server, one processor grabs the system lock, tries to do an I/O, gets hung up because of storage requirements below the 2gb line, and while that is happening, the other processor(s) request the lock and issue DIAG44 for a while. The current record for DIAG44 i think is something like 300,000 per second per processor. Serious problem. Affects many installations, some even know they are affected. Misterious slow downs from poor performing applications are the normal scapegoats. But SAP is affected, Oracle, NFS, probably SAMBA, and TAR all have this problem. Avoided if virtual machines are very small so they all fit in the 2GB. There is no relief in z/vm 5.1 from this. >From: Pieter Harder <[EMAIL PROTECTED]> > >>Yes, most likely I/O related. Any storage that CP references >>must be below the line. Doing any DIAG44? What is your I/O >>rate from the production server? > >Yes, there are large DIAG44 spikes around. I haven't determined yet who >is causing them. >I/O rate is moderate, no more than a few per second. > >>Is your server machine in Simulation wait (yet) > >No visible SIMW, only IOA. That is coming from hipersockets I think. > >>Can you graph the virtual machine i/o rate against the >>expanded storage rate? They should track almost 100%. > >No way they are tracking. Expanded rate is in the several dozen range >and I/O is just a few. > > >Best regards, >Pieter Harder > >[EMAIL PROTECTED] >tel +31-73-6837133 / +31-6-47272537 "If you can't measure it, I'm Just NOT interested!"(tm) /************************************************************/ Barton Robinson - CBW Internet: [EMAIL PROTECTED] Velocity Software, Inc Mailing Address: 196-D Castro Street P.O. Box 390640 Mountain View, CA 94041 Mountain View, CA 94039-0640 VM Performance Hotline: 650-964-8867 Fax: 650-964-9012 Web Page: WWW.VELOCITY-SOFTWARE.COM /************************************************************/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
