On Dec 27, 2007 9:25 AM, Klaus Johansen <[EMAIL PROTECTED]> wrote: > Our VM system pages extremely slowly: a long inactive Linux guest is paged in > from DASD by z/VM with approximately 1 MB/sec in an otherwise almost idle > system. The overall system page rate is 400-800 pages/second – half for > reading pages and half for writing pages. We have 12 paging disks (3390-9) > distributed over 2 LCUs and attached with 6 FICON channels – neither disks > nor channels are in any way a bottleneck according to our performance > readings.
I'm not familiar with your performance monitor. If yours includes tuning support, then those folks will be able to help you. But if you want to capture some raw monitor data, I'd be happy to browse that and see whether I can explain what you see. Drop me a note off-list if you're interested. I do spot a number there that might suggest your paging blocking is too low (happens when your paging space is very full). I also see you have MDC in XSTORE which is something you probably should not do anymore. You haven't told yet what level of z/VM you run, and there's a zillion of other questions I would have to ask when looking at this (all answered by the raw monitor data). > At the same time the main storage is badly utilized: Performance Toolkit > reports a storage utilization of 65-75% and it reports strange values for > "Total real Storage" and "Total available" storage: namely 0kb. The "storage utilization" number does not have much value these days. I suspect the low value might be due to MDC in main memory (which may drive your paging up, but does not explain poor paging). While I don't know whether the "total" comes from, it could very well be that your MONDCSS is not configured right and causes you to miss configuration data (I'm told even Performance Toolkit complains about it when that happens). It's the "config sample size" that is set on the MONITOR START command. Rob -- Rob van der Heij Velocity Software, Inc http://velocitysoftware.com/
