On Thursday, 08/31/2006 at 10:16 EST, James Melin <[EMAIL PROTECTED]> wrote: > I'm trying to discover what might possibly be running at 4:00 AM on all my > penguins that might cause excessive cumulative VM paging (we're over > committed real by 12-18%) at one time. > > Obviously something appears to be configured on all systems to do the same > thing at the same time.
> I see nothing that I can think of that would cause excessive VM paging, nor do > I see any after the fact evidence that my Linuxes were doing excessive > paging. I would expect to have seen massive swapping internally to Linux before > a VM paging event that would come close to exhausting the page pool > because of excessive real and xstor usage. If CP can hold the all of the Linux guests' active pages in real memory, then Linux can swap furiously while CP is not paging at all. But if there is not enough real memory to hold all the needed pages used by all of the active guests, plus all the memory that CP needs for himself, then CP will start to page. Linux swapping increases as processes within Linux start to contend for memory *within Linux*. The two aren't directly related. The problem you experienced is *exactly* why having all the guests' cron jobs fire at the same time is a Bad Idea. It's like opening a can of cat food in a room full of hungry cats. They all come running towards you at the same time, but you have only one can of catfood. Alan Altmark z/VM Development IBM Endicott ---------------------------------------------------------------------- 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
