On Mon, Jan 06, 2014 at 02:55:54PM +0800, 叶绍琛 wrote: > hi, all: > > > There is a problem when I use ceph rbd for qemu storage. I launch 4 virtual > machines, and start 5G random write test at the same time. Under such heavy > I/O, the network to > virtual machine almost unusable, the network latency is extremely big. > > > I had test another situation, when I use 'virsh attach-device' command to > attach rbd which mapped in my host machine(which run virtual machines), the > problem was not show again.
Does this mean you are comparing QEMU's rbd block driver against the Linux kernel rbd driver? > So, I think this must be qemu-rbd 's problem. Please try running jitterd to confirm that the guest vCPU is getting sufficient execution time: http://codemonkey.ws/cgit/jitterd.git/tree/jitterd.c This test will confirm that network I/O is performing poorly, not a starved guest CPU. > Here is my testing environment: > > > # virsh version > Compiled against library: libvirt 1.2.0 > Using library: libvirt 1.2.0 > Using API: QEMU 1.2.0 > Running hypervisor: QEMU 1.7.0 > > > In vm's xml, I define the rbd like this: > <disk type='network' device='disk'> > <driver name='qemu' type='raw' cache='none'/> > <source protocol='rbd' name='qemu/rbd-vm4'> > <host name='10.120.111.111' port='6789'/> > </source> > <auth username='libvirt'> > <secret type='ceph' uuid='38b66185-4117-47a6-90bd-64111c3fc5d2'/> > </auth> > <target dev='vdb' bus='virtio'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x06' > function='0x0'/> > </disk> > > > > > testing tool is : fio > io depth is : 32 > io engine is : libaio > io direct is open > > > > > Is there anyone met such a problem? > > > > > regards > > > Alan Ye > > > ------------------ > Alan Ye
