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Description of problem:
blkiotune cannot live update <weight> value into domain xml via --weight
Version-Release number of selected component (if applicable):
libvirt-1.2.17-4.el7.x86_64
How reproducible:
100%
Steps to Reproduce:
1.define and start a guest , get blkiotune as default
# virsh blkiotune r7
weight : 1000
device_weight :
device_read_iops_sec:
device_write_iops_sec:
device_read_bytes_sec:
device_write_bytes_sec:
2. set blkiotune with --weight
# virsh blkiotune r7 --weight 999
# virsh blkiotune r7
weight : 999
device_weight :
device_read_iops_sec:
device_write_iops_sec:
device_read_bytes_sec:
device_write_bytes_sec:
# virsh dumpxml r7|grep blkiotune
Nothing output .
3. define and start a guest like following
# virsh dumpxml r7-20 | grep blkiotune -A 5
<blkiotune>
<weight>888</weight>
<device>
......
4.set blkiotune with --weight
# virsh blkiotune r7-20 --weight 999
# virsh blkiotune r7-20
weight : 999
device_weight :
device_read_iops_sec:
device_write_iops_sec:
device_read_bytes_sec:
device_write_bytes_sec:
# virsh dumpxml r7-20 | grep blkiotune -A 5
<blkiotune>
<weight>888</weight>
<device>
.....
check in cgroup , the value has been changed.
# cat /sys/fs/cgroup/blkio/machine.slice/machine-qemu\guest-name.scope/blkio.weight
999
Actual results:
As step2 and step4, the value of weight cannot be live updated.
Expected results:
I think the value of <weight> should be live updated.
If it's not (because the default value 1000 is not displayed in domain xml); perhaps It's better give some info in man page or libvirt.org.
Additional info:
Upstream commit:
commit bf2788218ad29719467260aa4ecad6dc31c97046
Author: Luyao Huang <lhuang>
Date: Wed Aug 19 11:56:33 2015 +0800
qemu: Update blkio.weight value after successful set
https://bugzilla.redhat.com/show_bug.cgi?id=1253107
Make a call virCgroupGetBlkioWeight to re-read blkio.weight right
after it is set in order to keep internal data up-to-date.
Signed-off-by: Luyao Huang <lhuang>
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
https://rhn.redhat.com/errata/RHSA-2016-2577.html
Description of problem: blkiotune cannot live update <weight> value into domain xml via --weight Version-Release number of selected component (if applicable): libvirt-1.2.17-4.el7.x86_64 How reproducible: 100% Steps to Reproduce: 1.define and start a guest , get blkiotune as default # virsh blkiotune r7 weight : 1000 device_weight : device_read_iops_sec: device_write_iops_sec: device_read_bytes_sec: device_write_bytes_sec: 2. set blkiotune with --weight # virsh blkiotune r7 --weight 999 # virsh blkiotune r7 weight : 999 device_weight : device_read_iops_sec: device_write_iops_sec: device_read_bytes_sec: device_write_bytes_sec: # virsh dumpxml r7|grep blkiotune Nothing output . 3. define and start a guest like following # virsh dumpxml r7-20 | grep blkiotune -A 5 <blkiotune> <weight>888</weight> <device> ...... 4.set blkiotune with --weight # virsh blkiotune r7-20 --weight 999 # virsh blkiotune r7-20 weight : 999 device_weight : device_read_iops_sec: device_write_iops_sec: device_read_bytes_sec: device_write_bytes_sec: # virsh dumpxml r7-20 | grep blkiotune -A 5 <blkiotune> <weight>888</weight> <device> ..... check in cgroup , the value has been changed. # cat /sys/fs/cgroup/blkio/machine.slice/machine-qemu\guest-name.scope/blkio.weight 999 Actual results: As step2 and step4, the value of weight cannot be live updated. Expected results: I think the value of <weight> should be live updated. If it's not (because the default value 1000 is not displayed in domain xml); perhaps It's better give some info in man page or libvirt.org. Additional info: