[rhelv6-list] Limiting pvmove speed with control groups doesn't work as expected
Gianluca Cecchi
gianluca.cecchi at gmail.com
Tue Jul 26 15:51:15 UTC 2016
On Tue, Jul 26, 2016 at 4:47 PM, Barry Brimer wrote:
> Maybe ionice could help?
>
>
Thanks for your answer Barry, but It would be suboptimal in my opinion for
my target that is limiting read overall bandwith....
But I found it !!!
With iotop I see the PID of kcopyd that starts right after pvmove
command.... (the kcopyd pid is different every pvmove run, not a fixed
process)
[root at dbatest1 ~]# ps -ef|grep 11139
root 11139 2 1 17:40 ? 00:00:02 [kcopyd]
root 17103 19305 0 17:43 pts/0 00:00:00 grep 11139
BTW, kcopyd is child of kthreadd:
root 2 0 0 Jun29 ? 00:00:00 [kthreadd]
So I put kcopyd process into the control group too
# echo 11139 > /cgroup/blkio/30M/tasks
so that I now have pvmove process and kcopyd process
[root at dbatest1 ~]# cat /cgroup/blkio/30M/tasks
11139
12765
And in fact:
Total DISK READ: 30399.94 K/s | Total DISK WRITE: 30345.65 K/s
PID PRIO USER DISK READ> DISK WRITE SWAPIN IO COMMAND
11139 be/4 root 29970.89 K/s 0.00 K/s 0.00 % 0.00 % [kcopyd]
12765 be/4 root 65.40 K/s 0.00 K/s 0.00 % 0.91 % pvmove -i 20
/dev/mapper/360a9800037543543~v/mapper/3600a098038303769752b495147377868
36462 be/4 oracle11 20.93 K/s 15.70 K/s 0.00 % 0.08 % ora_ckpt_ALMTEST
8953 ?dif root 7.85 K/s 0.49 K/s 0.00 % 0.12 % qdiskd
20972 be/4 root 0.00 K/s 0.00 K/s 0.00 % 0.05 % [kjournald]
15733 be/4 root 0.00 K/s 1.31 K/s 0.00 % 0.00 % dsm_om_connsvcd
-run
14644 be/4 root 0.00 K/s 1.31 K/s 0.00 % 0.00 % nbdisco
40736 be/4 oracle11 0.00 K/s 15.70 K/s 0.00 % 0.05 % ora_ckpt_TEST
12337 rt/4 root 0.00 K/s 2.62 K/s 0.00 % 0.00 % corosync -f
and
Device: tps MB_read/s MB_wrtn/s MB_read MB_wrtn
sdaq 17.00 7.23 0.00 21 0
sdbf 17.33 7.44 0.00 22 0
sdcy 17.33 7.50 0.00 22 0
sddn 17.33 7.50 0.00 22 0
Thanks anyway ;-)
Gianluca
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