Hi Martin,
I have tried various methods to dientify the cause of this and took your
advice and used vmstat. I simply restarted the httpd process from the monit
web interface while the comand was running and got the following warning.
Description: cpu system usage of 50.0% matches resource limit [cpu
system usage>30.0%]
But vmstat doesnt show that level of usage at the point of alert. As you
can see there is some usage in the 3rd line of the output when i restarted
the httpd service but it doesnt seem enough to trigger an alert.
vmstat 1 10
procs -----------memory---------- ---swap-- -----io---- --system--
-----cpu-----
r b swpd free buff cache si so bi bo in cs us sy id
wa st
0 0 0 859596 114684 856908 0 0 4 6 81 77 0 0 99
0 0
0 0 0 859448 114684 856916 0 0 0 0 100 94 1 0 99
0 0
0 0 0 898352 114692 815600 0 0 0 168 555 605 23 15 61
1 0
Not sure if there are any other tests i can run to narrow this down a bit
further as it still isn't making sense.
Regards
Wayne
On 7 December 2011 08:27, Martin Pala <[email protected]> wrote:
> Hi Lawrence,
>
> the test which triggers the alert is "system" cpu => it's the time the
> system spend in kernel mode. The cpu usage could be triggered by some
> background kernel task, to verify the monit report matches the system cpu
> usage, you should use either "vmstat" or "top" instead of "ps".
>
> Best regards,
> Martin
>
>
> On Dec 6, 2011, at 1:19 PM, Lawrence, Wayne wrote:
>
> Hi Igor,
>
> the operating system is RHEL6 and monit version is 5.3.1
>
> this is what i have in my config
>
> if cpu usage (user) > 70% then alert
> if cpu usage (system) > 30% then alert
> if cpu usage (wait) > 20% then alert
>
> this is one of the errors
> Description: cpu system usage of 50.0% matches resource limit [cpu system
> usage>30.0%]
>
> this is what i get in /var/log/messages
> Dec 6 12:01:29 <hostname-removed> monit[864]: <hostname-removed> cpu
> system usage of 50.0% matches resource limit [cpu system usage>30.0%]
> Dec 6 12:02:29 <hostname-removed> monit[864]:
> <hostname-removed><hostname-removed>' cpu system usage check succeeded
> [current cpu system usage=0.9%]
>
> this is the output of ps --no-headers -A -o "%*cpu* sz ucomm" | sort
> -k1nr | head -20
>
> 12:01:29 up 4 days, 20:24, 2 users, load average: 0.04, 0.01, 0.00
> total used free shared buffers cached
> Mem: 2055108 1092176 962932 0 53156 811864
> -/+ buffers/cache: 227156 1827952
> Swap: 4128760 0 4128760
> 1.2 44308 perl
> 0.0 0 aio/0
> 0.0 0 async/mgr
> 0.0 0 ata/0
> 0.0 0 ata_aux
> 0.0 0 bdi-default
> 0.0 0 cpuset
> 0.0 0 crypto/0
> 0.0 0 events/0
> 0.0 0 ext4-dio-unwrit
> 0.0 0 flush-253:0
> 0.0 0 jbd2/dm-0-8
> 0.0 0 kacpi_hotplug
> 0.0 0 kacpi_notify
> 0.0 0 kacpid
> 0.0 0 kauditd
> 0.0 0 kblockd/0
> 0.0 0 kdmflush
> 0.0 0 khelper
> 0.0 0 khubd
>
> Have to say i am at a total loss as there is no way the usage figures are
> accurate.
> If there is any other info i can supply that will be useful please let me
> know.
>
> Regards
>
> Wayne
>
>
> On 6 December 2011 12:03, Igor Homyakov
> <[email protected]>wrote:
>
>> Hi Lawrence,
>>
>> Could you be a little bit more specific ? Please provide information
>> about you operation system, monit version on which the problem
>> occurred and so on.
>>
>> Regards
>> Igor Homyakov
>>
>> On Tue, Dec 6, 2011 at 15:35, Lawrence, Wayne
>> <[email protected]> wrote:
>> > Hi,
>> >
>> > I have a few CPU usage checks in my monitrc but it seems monit is
>> > misreporting the usage.
>> >
>> > I have run several tests and it seems that monit is multiplying the
>> actual
>> > usage by 10.
>> >
>> > I ran a process with top running in another shell and CPU usage for the
>> user
>> > was never above 10% yet monit informed me that there was 100% cpu usage.
>> >
>> > I have tried various configurations including the one that came with the
>> > default config for system cpu monitoring and all seem to demonstrate the
>> > same issue.
>> >
>> > Any advice welcomed on this
>> >
>> > Regards
>> >
>> > Wayne Lawrence
>> >
>> >
>> >
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