[ovirt-users] Performance of cloning

[Gianluca Cecchi]

Hello,
I'm on 4.1.5 and I'm cloning a snapshot of a VM with 3 disks for a total of
about 200Gb to copy
The target I choose is on a different domain than the source one.
They are both FC storage domains, with the source on SSD disks and the
target on SAS disks.

The disks are preallocated

Now I have 3 processes of kind:
/usr/bin/qemu-img convert -p -t none -T none -f raw
/rhev/data-center/59b7af54-0155-01c2-0248-000000000195/fad05d79-254d-4f40-8201-360757128ede/images/8f62600a-057d-4d59-9655-631f080a73f6/21a8812f-6a89-4015-a79e-150d7e202450
-O raw
/rhev/data-center/mnt/blockSD/6911716c-aa99-4750-a7fe-f83675a2d676/images/c3973d1b-a168-4ec5-8c1a-630cfc4b66c4/27980581-5935-4b23-989a-4811f80956ca

but despite capabilities it seems it is copying using very low system
resources.
I see this both using iotop and vmstat

vmstat 3 gives:
----io---- -system-- ------cpu-----
bi    bo   in   cs us sy id wa st
2527   698 3771 29394  1  0 89 10  0


iotop -d 5 -k -o -P gives:

Total DISK READ :     472.73 K/s | Total DISK WRITE :    17.05 K/s
Actual DISK READ:    1113.23 K/s | Actual DISK WRITE:      55.86 K/s
  PID  PRIO  USER    DISK READ>  DISK WRITE  SWAPIN      IO    COMMAND

 2124 be/4 sanlock   401.39 K/s    0.20 K/s  0.00 %  0.00 % sanlock daemon
 2146 be/4 vdsm       50.96 K/s    0.00 K/s  0.00 %  0.00 % python
/usr/share/o~a-broker --no-daemon
30379 be/0 root        7.06 K/s    0.00 K/s  0.00 % 98.09 % lvm vgck
--config  ~50-a7fe-f83675a2d676
30380 be/0 root        4.70 K/s    0.00 K/s  0.00 % 98.09 % lvm lvchange
--conf~59-b931-4eb61e43b56b
30381 be/0 root        4.70 K/s    0.00 K/s  0.00 % 98.09 % lvm lvchange
--conf~83675a2d676/metadata
30631 be/0 root        3.92 K/s    0.00 K/s  0.00 % 98.09 % lvm vgs
--config  d~f6-9466-553849aba5e9
 2052 be/3 root        0.00 K/s    2.35 K/s  0.00 %  0.00 % [jbd2/dm-34-8]
 6458 be/4 qemu        0.00 K/s    4.70 K/s  0.00 %  0.00 % qemu-kvm -name
gues~x7 -msg timestamp=on
 2064 be/3 root        0.00 K/s    0.00 K/s  0.00 %  0.00 % [jbd2/dm-32-8]
 2147 be/4 root        0.00 K/s    4.70 K/s  0.00 %  0.00 % rsyslogd -n
 9145 idle vdsm        0.00 K/s    0.59 K/s  0.00 % 24.52 % qemu-img
convert -p~23-989a-4811f80956ca
13313 be/4 root        0.00 K/s    0.00 K/s  0.00 %  0.00 % [kworker/u112:3]
 9399 idle vdsm        0.00 K/s    0.59 K/s  0.00 % 24.52 % qemu-img
convert -p~51-9c8c-8d9aaa7e8f58
 1310 ?dif root        0.00 K/s    0.00 K/s  0.00 %  0.00 % multipathd
 3996 be/4 vdsm        0.00 K/s    0.78 K/s  0.00 %  0.00 % python
/usr/sbin/mo~c /etc/vdsm/mom.conf
 6391 be/4 root        0.00 K/s    0.00 K/s  0.00 %  0.00 % [kworker/u112:0]
 2059 be/3 root        0.00 K/s    3.14 K/s  0.00 %  0.00 % [jbd2/dm-33-8]

Is it expected? Any way to speed up the process?

Thanks,
Gianluca
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