20.45. Display or Set Block I/O Parameters

The blkiotune command sets or displays the I/O parameters for a specified guest virtual machine. The following format should be used:
# virsh blkiotune domain [--weight weight] [--device-weights device-weights] [---device-read-iops-sec -device-read-iops-sec] [--device-write-iops-sec device-write-iops-sec] [--device-read-bytes-sec device-read-bytes-sec] [--device-write-bytes-sec device-write-bytes-sec] [[--config] [--live] | [--current]]
More information on this command can be found in the Virtualization Tuning and Optimization Guide