LinuxQuestions.org - [SOLVED] Netdata reports 10min cpu iowait

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Netdata reports 10min cpu iowait

Netdata has been running since 1 Aug however since 4 Aug it's been reporting the below:

Code:

"3:26:49 AM",system.cpu,"10min cpu iowait",16.5%,CLEAR

"3:19:49 AM",system.cpu,"10min cpu iowait",41.2%,WARNING

"8/8/2020 3:32:49 AM",system.cpu,"10min cpu iowait",16.9%,CLEAR

"8/8/2020 3:19:49 AM",system.cpu,"10min cpu iowait",40.9%,WARNING

"8/7/2020 3:28:48 AM",system.cpu,"10min cpu iowait",16.8%,CLEAR

"8/7/2020 3:19:48 AM",system.cpu,"10min cpu iowait",41.1%,WARNING

"8/4/2020 3:31:46 AM",system.cpu,"10min cpu iowait",16.2%,CLEAR

"8/4/2020 3:19:46 AM",system.cpu,"10min cpu iowait",40.5%,WARNING

Some system info:

Code:

Kernel        Linux 5.4.0-42-generic (x86_64)

Version        #46~18.04.1-Ubuntu SMP Fri Jul 10 07:21:24 UTC 2020

Distribution        Ubuntu 18.04.5 LTS

Processors

Package Information

Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz        0        0:0        2731.74 MHz

Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz        1        0:1        2787.58 MHz

MemTotal Total Memory        15326184 KiB

SwapTotal        Virtual Memory        4089852 KiB

It seems to start at the same time within a few seconds. I see nothing odd in syslog. The only thing that is running during that time is an rsync backup to an external usb drive. It starts at 03:10am each morning and ends depending on how much data is backed up. For instance on 08/04 it started at 03:10 and ended 03:25. Other days noted in the log:

Code:

04/07 03:10 - 03:22

04/08 03:10 - 03:26

04/11 03:10 - 03:20

Honestly I'm not sure if this is even anything to be concerned about. If any more data is needed I'd be happy to provide it.

iowait normally means disk IO. The fact that it happens at the time the backup runs is not surprising.

Use top or vmstat to check if you have a large iowait figure now, and iostat to check your current IO activity. sar also reports these metrics.

Ran iostat, it all looks good to me so I'll agree with you that it's more than likely the backup causing it. Just something I never noticed before running Netdata.

Code:

iostat -c 5 25

Linux 5.4.0-42-generic (localhost)        08/11/2020        _x86_64_        (2 CPU)



avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          12.78    0.03    4.02    1.38    0.00  81.80

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          5.14    0.00    2.82    0.00    0.00  92.04

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          4.77    0.00    2.03    0.30    0.00  92.90

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          15.28    0.00    5.93    1.71    0.00  77.09

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          8.76    0.00    3.02    1.81    0.00  86.40

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          5.34    0.00    2.62    0.20    0.00  91.83

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          15.94    0.00    3.83    0.20    0.00  80.02

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          13.69    0.00    4.70    0.90    0.00  80.72

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          14.21    0.00    4.74    0.71    0.00  80.34

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          35.77    0.00  12.58    0.09    0.00  51.55

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          30.41    0.00    8.69    4.44    0.00  56.47

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          43.50    0.00  14.00    3.02    0.00  39.48

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          14.45    0.00    2.64    0.00    0.00  82.91

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          9.01    0.00    3.40    0.40    0.00  87.19

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          5.84    0.00    3.22    0.00    0.00  90.95

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          17.60    0.00    6.20    0.40    0.00  75.80

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          8.81    0.00    4.20    1.60    0.00  85.39

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          5.99    0.00    3.69    0.30    0.00  90.02

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          15.43    0.00    4.51    0.30    0.00  79.76

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          17.20    0.00    5.30    1.90    0.00  75.60

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          10.01    0.00    3.70    0.50    0.00  85.79

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          8.57    0.00    3.69    1.10    0.00  86.64

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          5.34    0.00    3.12    0.60    0.00  90.94

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          20.44    0.00    6.91    2.00    0.00  70.64

avg-cpu:  %user  %nice %system %iowait  %steal  %idle

          12.54    0.00    3.78    3.78    0.00  79.90

I'll mark this thread as solved, appreciate the reply

Quote:

Originally Posted by Toadman (Post 6154914)

Just something I never noticed before running Netdata.

Just another questionable metric used inappropriately. Get some users to log on around then and play some games. Problem solved.