it seems to be the same thing as recently reported on the kvm list (related to virtio-blk), I will follow up there
regarding my memory calculations for the host, for an system that only has kvm virtual machines, nothing else considering an overhead of 20% of the guest memory is sufficient ? should I reserve, some additional memory for the host kernel ? I am trying to come up with an scheme to dimension host machines that have 12, 18 and 24gb ram, and to avoid swap usage Razvan RADU +40 (72) 7772218 / mobile On 04/21/2010 02:22 PM, Dor Laor wrote: > On 04/20/2010 05:17 PM, Razvan Radu wrote: >> hello, >> >> after running an stress program in the guest for 6 to 24 hours the >> qemu-kvm process uses up all the available memory and gets killed by >> oom, is this an bug or an configuration problem ? >> >> host: >> arch: intel i7 12gb ram >> fedora 12 updated as of 2010-04-19 with fedora-virt packages >> kernel: 2.6.32.11-99.fc12.x86_64 >> qemu: qemu*0.12.3-7.fc12.x86_64, also tested with >> qemu*0.12.3-6.fc12.x86_64 >> libvirt: libvirt*0.7.7-2.fc12.x86_64 >> qemu command: /usr/bin/qemu-kvm -S -M pc-0.11 -enable-kvm -m 3072 -smp >> 4,sockets=4,cores=1,threads=1 -name guest-00574 -uuid >> 3f26c499-b029-3e1c-2410-fd197b262057 -nodefaults -chardev >> socket,id=monitor,path=/var/lib/libvirt/qemu/guest-00574.monitor,server,nowait >> >> >> -mon chardev=monitor,mode=readline -rtc base=utc -boot dc -drive >> if=none,media=cdrom,id=drive-ide0-1-0 -device >> ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -drive >> file=/dev/hdd.img/guest-00574-1,if=none,id=drive-virtio-disk0,boot=on,cache=none >> >> >> -device >> virtio-blk-pci,bus=pci.0,addr=0x4,drive=drive-virtio-disk0,id=virtio-disk0 >> >> -device >> virtio-net-pci,vlan=0,id=net0,mac=54:52:00:00:00:49,bus=pci.0,addr=0x5 >> -net tap,fd=21,vlan=0,name=hostnet0 -usb -device usb-tablet,id=input0 >> -vnc 0.0.0.0:2 -vga cirrus -device >> virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3 >> >> guest: >> CentOS release 5.4 >> kernel: 2.6.18-164.15.1.el5 >> >> stress program: >> http://weather.ou.edu/~apw/projects/stress/ >> comman line: ./stress -v -c 4 -m 4 --vm-bytes 800M -d 4 --hdd-bytes 100M >> -t 100000 >> >> >> the qemu process is constantly using more and more memory and after a >> while it get killed >> I have tested with: >> - no hugepages >> - hugepages >> - lvm >> - qcow2 image files >> - cache=writeback >> - cache=none >> all resulted in the same memory usage pattern (slowly growing) >> >> >> do you know of an formula for calculating the memory overhead for >> qemu-kvm (without an potential memory leak ...) ? >> I have noticed an 20% overhead with and without hugepages (pmap reported >> a total of 1.2G for an 1G guest and 3.6G total for an 3G guest) >> is 20% an correct assumption (it seems a little high) ? >> I have observed the same overhead with hugepages, is this normal ? > > The is ruffly looks fine, in addition to the guest's ram there is > overhead for pci config space of the devices, qcow2 metadata, etc. > > How much ram do you have on your host? Please provide the top data, > vmstat 1 and slabtop info. > > qemu do copy IO requests but eventually each request should be freed. > >> >> >> thanks, >> > _______________________________________________ virt mailing list [email protected] https://admin.fedoraproject.org/mailman/listinfo/virt
