On 12/1/05, Harris, Nick J. <[EMAIL PROTECTED]> wrote: > Anyone using Performance Toolkit for VM to monitor Linux guests? > > Thanks for the responses! > > Nick > > -----Original Message----- > From: Linux on 390 Port [mailto:[EMAIL PROTECTED] Behalf Of > Nix, Robert P. > Sent: Thursday, December 01, 2005 9:34 AM > To: [email protected] > Subject: Re: Linux Guest CPU usage > > > The first step would be to make the Linux guests smaller. Unless your > application will not run in less, 2gig is way too much memory, and will work > against your performance. The logic to this follows: > > Linux was designed to run on a free standing box. And, it was designed to be > efficient while doing it. To that end, any and all "free" memory in the > system is used to cache disk. This speeds things up and improves the overall > performance of the box. Everyone's happy with the results. > > But then you move Linux into a virtual environment. It still has 2 gig of > memory, and it has enough room for its application, so it happily caches disk > into the remaining memory, to improve its performance. But wait a sec... It's > memory is really VIRTUAL memory on zVM. And because it has so much, and it's > using it instead of doing disk I/O's, there's no locality of reference within > the image, and it has a huge working set on zVM. While each Linux image does > no swapping (normally a good thing), zVM is doing a huge amount of paging > trying to keep these oversized working sets in storage as the virtual > machines need them. Oh, and zVM is caching disk on its own too, so most of > the disk references are double-cached, using even more memory. You're > spending much of your time in zVM paging that really isn't necessary. > > The solution is to reduce the virtual machine size of the Linux images until > they just begin to swap. Then, maybe, give just a little back. This should > end up being the ideal machine size for the load being placed on it, and will > reduce the working set size (no Linux caching, because there isn't enough > available free memory to support it), which will reduce the zVM paging, which > will improve the response of all your Linux images, and allow you to place > more images in the physical box. > > Whenever a user tells me that they need more memory to improve their > response, I first look at reducing their memory to see if that wouldn't be a > better solution for them and everyone else on the box. > > > -- > Robert P. Nix Mayo Foundation > RO-OC-1-13 (new loc) 200 First Street SW > 507-284-0844 Rochester, MN 55905 > ----- > "In theory, theory and practice are the same, but > in practice, theory and practice are different." > > -----Original Message----- > From: Linux on 390 Port [mailto:[EMAIL PROTECTED] On Behalf Of Harris, Nick J. > Sent: Thursday, December 01, 2005 8:43 AM > To: [email protected] > Subject: Linux Guest CPU usage > > Hello All, > > Is there a way to monitor CPU usage for each Linux guest from VM? > > We are running SUSE9 guests on z/VM 5.1 which is all new to us. We were > having performance problems with the Linux guests > so we added 8 GIG of memory for a total of 11 GIG on the IFL with one CPU and > each Linux guests is configured with 2G each. > One of our vendors found a couple of patches for Linux that addresses memory > leaks (my understanding) which we think solved our performance problems and > not the additional memory. So now we are trying to verify that. These Linux > guests are screaming now and if we don't need the memory we will send it back. > > TIA! > > > Thanks, > Nick Harris > Lead Systems Programmer > Texas Farm Bureau Mutual Insurance Company > P.O. Box 2689, Waco, TX. 76702 > 254.751.2259 > [EMAIL PROTECTED] > > ---------------------------------------------------------------------- > 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 > > ---------------------------------------------------------------------- > 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 > > ---------------------------------------------------------------------- > 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 > Sorry I missed most of the action. are you running zOS in the same box? if you do, RMF 70 can help and then based on sar for each Linux LPAR you can normalized. With zVM should be easier using the VM Toolkit. The challenge is for accounting purposes. Linux for z-Series does not have a good accounting package but there are ways around with some of the other native tools.
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