Why are you using vhd instead of qcow2? I would wager it's a combination of the vhd format having some bug. Try with qcow2 first.
On 22 February 2017 at 21:17, Mimiko <vbv...@gmail.com> wrote: > Hello. > > I already wrote to qemu mail list and didn't find an answer. > > I've setup qemu / kvm on Debian Wheezy to host some Debian Jessie guests. > I create disk like this: > > virsh vol-create-as --pool default --name root.vhd --capacity 50G --format > vpc > > Then create a virtual with this: > virt-install --connect qemu:///system \ > --ram 2048 \ > --vcpus=4 \ > --cpuset=auto \ > --pxe \ > --os-type linux \ > --boot network,hd,menu=on \ > --disk vol=default/root.vhd,device=disk,bus=virtio,cache=writethrough \ > --network=bridge:br0,model=virtio \ > --noautoconsole \ > --hvm \ > --autostart \ > --check-cpu > > After setting up the system I've got poor disk performance. > Using > > time dd if=/dev/zero of=/tmp/test oflag=direct bs=64k count=16000 > > I get 1048576000 bytes (1.0 GB) copied, 397.473 s, 2.6 MB/s > > I've changed cache to writeback and got 20MB/s with this test. But copying > a file to this virtual using samba gives me no more of 2 MB/s. > > I've tested network connectivity with iperf and got around 750Mbit/s, > which I think is satisfactory. > > I will not want to use raw devices, as it is not self expanded and will > use whole space regardless of how much real data occupy. > > libvirtd (libvirt) 0.9.12.3 > > Is there a way to increase disk speed to at least 50MB/s ? > > As suggested by other to test: > > I've created a raw disk of 10GB and attached to VM and mounted it. The > speed is same - 2MB. > As per same cifs/samba access to / on the host - the speed is 180MB+, as > there are 2 network interfaces in alb bond. > > > time dd if=/dev/zero of=/vdisks/test oflag=direct bs=64k count=16000 > 16000+0 records in > 16000+0 records out > 1048576000 bytes (1.0 GB) copied, 0.970587 s, 1.1 GB/s > > real 0m0.972s > user 0m0.008s > sys 0m0.856s > > /vdisks reside on a raidz2 zfs pool via PCI-E hardware raid used in IT > mode to allow ZFS software raid. > > > /usr/bin/kvm --version > QEMU emulator version 1.1.2 (qemu-kvm-1.1.2+dfsg-6+deb7u19, Debian), > Copyright (c) 2003-2008 Fabrice Bellard > > > virsh dumpxml YOURVMNAME > tmp.xml > <domain type='kvm' id='10'> > <name>srv</name> > <uuid>c23810c8-fe96-12df-5769-5a7a80c3c35f</uuid> > <memory unit='KiB'>2097152</memory> > <currentMemory unit='KiB'>2097152</currentMemory> > <vcpu placement='static'>4</vcpu> > <os> > <type arch='x86_64' machine='pc-1.1'>hvm</type> > <boot dev='hd'/> > <boot dev='network'/> > <bootmenu enable='yes'/> > </os> > <features> > <acpi/> > <apic/> > <pae/> > </features> > <clock offset='utc'/> > <on_poweroff>destroy</on_poweroff> > <on_reboot>restart</on_reboot> > <on_crash>restart</on_crash> > <devices> > <emulator>/usr/bin/kvm</emulator> > <disk type='file' device='disk'> > <driver name='qemu' type='vpc' cache='writeback'/> > <source file='/vdisks/root.vhd'/> > <target dev='vda' bus='virtio'/> > <alias name='virtio-disk0'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x04' > function='0x0'/> > </disk> > <controller type='usb' index='0'> > <alias name='usb0'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x01' > function='0x2'/> > </controller> > <interface type='bridge'> > <mac address='52:54:00:de:83:2d'/> > <source bridge='br0'/> > <target dev='vnet0'/> > <model type='virtio'/> > <alias name='net0'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x03' > function='0x0'/> > </interface> > <serial type='pty'> > <source path='/dev/pts/4'/> > <target port='0'/> > <alias name='serial0'/> > </serial> > <console type='pty' tty='/dev/pts/4'> > <source path='/dev/pts/4'/> > <target type='serial' port='0'/> > <alias name='serial0'/> > </console> > <input type='mouse' bus='ps2'/> > <graphics type='vnc' port='59081' autoport='no' listen='0.0.0.0'> > <listen type='address' address='0.0.0.0'/> > </graphics> > <video> > <model type='cirrus' vram='9216' heads='1'/> > <alias name='video0'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x02' > function='0x0'/> > </video> > <memballoon model='virtio'> > <alias name='balloon0'/> > <address type='pci' domain='0x0000' bus='0x00' slot='0x08' > function='0x0'/> > </memballoon> > </devices> > <seclabel type='none'/> > </domain> > > Any help please. > >
