Okay, I found out additional infos regarding my problem. As it seems, the fact that the libvirts ksm dynamically manages the memory pages, which obviously leads to a stabilization of used memory, when the VMs virtual memory is utilized to the maximum. This is why I deactivated ksm and voila: Now the real memory stays utilized as well as the virtual memory, and doesnt handle clean memory pages anymore.
However, I have another problem now after I finish the utilization of my VM (which means, I kill the util. process, thus making all my virtual memory free again), the real host memory still stays utilized. What could be the reason that my VM shows 0% mem. util., while the physical host still has 100%??? I thought maybe the reason could be that ONE accesses the virto_balloon? Can the authors maybe give me an answer to this? All in all, is there any way to make this work to fully utilize a VM for 10 min. and the host stays utilized as well, and when I stop the utilization that both the VM and host memory decrease??? Thanks! ________________________________ Von: Steven Timm < <http://lists.opennebula.org/listinfo.cgi/users-opennebula.org> timm at fnal.gov> An: Adnan Pasic < <http://lists.opennebula.org/listinfo.cgi/users-opennebula.org> pqado at yahoo.de> Cc: " <http://lists.opennebula.org/listinfo.cgi/users-opennebula.org> users at lists.opennebula.org" < <http://lists.opennebula.org/listinfo.cgi/users-opennebula.org> users at lists.opennebula.org> Gesendet: 16:08 Mittwoch, 23.November 2011 Betreff: Re: [one-users] A question about the utilization of VMs What hypervisor are you using? If you are using KVM then this behavior is normal, KVM only actually occupies the amount of RAM that the virtual machine is actually using at the time and OpenNebula reports the usage accordingly. this makes it possible to overbook and put 16 2-GB KVM VM's on a machine that has less physical RAM than that. Steve Timm On Wed, 23 Nov 2011, Adnan Pasic wrote: > Hello guys, I have a problem with understand one specific behaviour and I hope that this community might help me with it. Anyway, I am writing my diploma thesis using OpenNebula and so far it has done everything I imagined and wanted it to do. I deploy VMs and utilize every one of them with the tool ÿÿlookbusyÿÿ. On normal physical hosts, lookbusy works perfectly, utilizing the CPU/Memory as I set it and doesnÿÿt stop the utilization until the whole process is killed. When I utilize my VM, however, I noticed the VMs being utilized for approx. 2 minutes, but afterwards I can see a falling trend of utilized memory on the physical host. For instance, I utilize the memory of the VM by 2 GB ÿÿ thus, the physical host shows the same utilization too. Nevertheless, after 2 minutes, the utilization on the physical host starts decreasing and stops at about 500MB of utilized memory, although the VM shows the whole time a full utilization of 2GB ! Do you know what could be the reason? Maybe it has something to do with the scheduler, or I donÿÿt know? Please help me with this, as this is a crucial part of my diploma thesis and I got stuck!!! Thanks in advance. Regards, Adnan
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