Re: [libvirt-users] Getting libvirt Error when setting IO tune read_bytes_sec value using libvirt API virDomainSetBlockIotune
On 09.05.2013 14:02, vikrant verma wrote:
Hi All,
I am setting the value for "read_bytes_sec" using the following API code
virDomainSetBlockIoTune(dom, "/mnt/tmpsdb/FileVM1", parainfoPtr,
nparams, 2);
I am succesfully able to set this value and i can read it back using the API
virDomainGetBlockIoTune(dom,"/mnt/tmpsdb/FileVM1",parainfoPtr,&nparams,2);
But after setting this value when i shutdown my VM and start it again I
am getting following error -
ibvirtError: internal error Process exited while reading console log
output: qemu-system-x86_64: -drive
file=/mnt/tmpsdb/FileVM1,if=none,id=drive-ide0-1-1,format=raw,bps_rd=1048576:
Invalid parameter 'bps_rd'
Interesting. What's the qemu version? bps_rs has been introduced in
qemu-1.1 IIRC.
Note - when i see dumpxml of the VM following lines are got added after
setting the iotunes for read_bytes_sec
<iotune>
<read_bytes_sec>1048576</read_bytes_sec>
</iotune>
Yep, that's correct. If you don't need this setting anymore, just delete
it (e.g. by using virsh edit) and you should be able to start the domain
up again.
Please help me. Also i wanted to know whether we can set block IO tune
for a VM using the above API. Is it same as the IO throttling provided
by cgroup?
Michal