On Thu, Mar 07, 2013 at 12:57:55PM +0100, Wolfgang Hennerbichler wrote: > I'm running a virtual machine with the following command: > > LC_ALL=C > PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin > QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-1.0 -enable-kvm -m 4096 -smp > 2,sockets=2,cores=1,threads=1 -name korfu_ceph -uuid > a9131b8f-d087-26f4-2ca9-018505f11838 -nodefconfig -nodefaults -chardev > socket,id=charmonitor,path=/var/lib/libvirt/qemu/korfu_ceph.monitor,server,nowait > -mon chardev=charmonitor,id=monitor,mode=control -rtc base=localtime > -no-shutdown -device lsi,id=scsi0,bus=pci.0,addr=0x4 -drive > file=rbd:rd/korfu:rbd_cache=1:mon_host=rd-clusternode21\:6789\;rd-clusternode22\:6789,if=none,id=drive-ide0-0-0,format=raw > -device > ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0,bootindex=1 > -usb -vnc 127.0.0.1:0 -vga std -device > virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x5 > > kvm-version is that from ubuntu LTS: 1.0+noroms-0ubuntu14.7 > > When I read or write big files the system basically gets unusable > (mouse-cursor in VNC jerks across the screen, i/o is mostly on > blocking). I know it is related to ceph in a way, but also to KVM, as it > seems that there a lot of IRQ's happening (or how do you explain the > mourse cursor in VNC jerking and lagging behind time?_) . Ceph Mailing > List doesn't really help. High CPU load doesn't hurt the machine, it's > only Harddisk I/O. Oh, and the main host running kvm doesn't really > suffer, too. some i/o waiting, but not really swapping or something. > > Here's my libvirt-config if it is of any help: > http://pastie.org/6411055 > > any hints would REALLY be appreciated... Please try using virtio-blk instead of IDE. If the guest still jerks try using the Linux rbd block driver instead of QEMU -drive rbd:. I haven't used Ceph much but there should be documentation on attaching a RADOS block device to your Linux host. Tell QEMU to use the RADOS block device like a regular file (you are now using the kernel driver instead of QEMU code to talk to the Ceph cluster). Please let us know the outcome. If you find that virtio-blk does not make much difference but using the kernel rbd driver does, then this suggests there is a bug in QEMU's block/rbd.c. Stefan -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
