qemu/docs/throttle.txt

170 group named using the throttling.group parameter. If this parameter is
172 be used as the group name.
175 document apply to the combined I/O of all members of a group.
179    -drive file=hd1.qcow2,throttling.iops-total=6000,throttling.group=foo
180    -drive file=hd2.qcow2,throttling.iops-total=6000,throttling.group=foo
181    -drive file=hd3.qcow2,throttling.iops-total=3000,throttling.group=bar
182    -drive file=hd4.qcow2,throttling.iops-total=6000,throttling.group=foo
183    -drive file=hd5.qcow2,throttling.iops-total=3000,throttling.group=bar
186 Here hd1, hd2 and hd4 are all members of a group named 'foo' with a
188 is left alone (technically it is part of a 1-member group).
191 I/O requests on several drives of the same group they will be
198    - I/O limits are shared within the same group, so new values will
201      group, the last one wins.
203    - If 'group' is unset it is assumed to be the current group of that
204      drive. If the drive is not in a group yet, it will be added to a
205      group named after the device name.
207    - If 'group' is set then the drive will be moved to that group if
209      specified in the parameters will be applied to the new group
213      case the device will be removed from its group and the rest of
214      its members will not be affected. The 'group' parameter is
266 them must be assigned to a group that contains the actual I/O limits.
267 Different filters can use the same group so the limits are shared as
270 A group can be created using the object-add QMP function:
274        "qom-type": "throttle-group",
283 throttle-group has a 'limits' property (of type ThrottleLimits as
287 A throttle-group can also be created with the -object command line
292    -object throttle-group,id=group0,x-iops-total=1000,x-bps-write=2097152
298 Once we have a throttle-group we can use the throttle block filter,
319         "throttle-group": "group0",
326    -drive driver=throttle,throttle-group=group0,
338    -object throttle-group,id=limits0,x-iops-total=2000
339    -object throttle-group,id=limits1,x-iops-total=2500
340    -object throttle-group,id=limits2,x-iops-total=3000
341    -object throttle-group,id=limits012,x-iops-total=4000
347    -drive driver=throttle,throttle-group=limits012,
348           file.driver=throttle,file.throttle-group=limits0
350    -drive driver=throttle,throttle-group=limits012,
351           file.driver=throttle,file.throttle-group=limits1
353    -drive driver=throttle,throttle-group=limits012,
354           file.driver=throttle,file.throttle-group=limits2