[CentOS] CPU utils almost 100%-- solved

Mon Jul 6 19:51:01 UTC 2009
fabian <fabian at baladia.gov.kw>

Dear Guys

Thanks and apprecite your quick replies
By the way i had stated solving the problem of almost 100% CPU utulization
starting everyday at 4 am and ending at 10 am in a very crude way
top was reporting 95% wa

i started to check the crontab file and noticed that the
cron.daily entry in the file sarts at 4 am

and in the directory i found


-rwxr-xr-x   1 root root   133 Jul  6 16:59 00webalizer
-rwxr-xr-x   1 root root   379 Jul  6 17:02 0anacron
lrwxrwxrwx   1 root root    39 Nov  9  2008 0logwatch ->
/usr/share/logwatch/scripts/logwatch.pl
drwxr-xr-x   2 root root  4096 Jul  5 21:25 backup
-rw-r--r--   1 root root    62 Jul  6 17:37 clamav
-rwxr-xr-x   1 root root   118 Jul  6 17:00 cups
-rwxr-xr-x   1 root root   456 Nov  3  2008 freshclam
-rwxr-xr-x   1 root root    26 Jul  6 17:00 havp
-rwxr-xr-x   1 root root   180 Dec  2  2007 logrotate
-rwxr-xr-x   1 root root   418 Jan  6  2007 makewhatis.cron
-rwxr-xr-x   1 root root   137 Jul  6 17:23 mlocate.cron
-rwxr-xr-x   1 root root  2181 Jun 21  2006 prelink
-rwxr-xr-x   1 root root   114 Jul  6 17:01 rpm
-rwxr-xr-x 1 root root   290 Jul  5 21:24 tmpwatch


i started movies some of thes files to difereent directory and finally
found that it was the below file that was the culprit

-rwxr-xr-x 1 root root   290 Jul  5 21:24 tmpwatch
-------
the contents of the file was

/usr/sbin/tmpwatch -x /tmp/.X11-unix -x /tmp/.XIM-unix -x /tmp/.font-unix \
        -x /tmp/.ICE-unix -x /tmp/.Test-unix 240 /tmp
/usr/sbin/tmpwatch 720 /var/tmp
for d in /var/{cache/man,catman}/{cat?,X11R6/cat?,local/cat?}; do
    if [ -d "$d" ]; then
        /usr/sbin/tmpwatch -f 720 "$d"
    fi
done
----------------

now everything works fine without this file in the /etc/cron.daily directory
so the tmpwatch was the culprit cause the CPU wait state to almost 99 %
for almost 6 hrs
but jus would like to know if this particular script has any signifance or
any perfomance issue and my system will run perfect without the file


apprecite you help


regards

Fabian




> fabian wrote:
>>> 2009/7/5 fabian <fabian at baladia.gov.kw>
>>>
>>>> i notced recently that the cpu utilization peaks to abt 100 % at 4 am
>>>> every day and becomes normall at 10 am
>>>>
>>>>
>>>> cpu 4.5%us   2.3% sy  0.0%ni 2% id   95% wa
>>>>
>>>> notice the 95% wa
>>>>
>>>>
>>> It looks like you might be misreading the idle % for CPU activity.  A
>>> 95%
>>> idle shows the system is not doing much.
>>>
>>
>> so sorry abouyt my typing
>>
>> its cpu==>4.5%us
>> sy==> 2.3%
>> ni==> 0.0%
>> id==> 2 %
>> wa==> 95%
>>
>>
>> so the wa=95 %
>>
>> this starts about 4 am and stops about 10 am
>> then the CPU idle time is always between 90% to 99%
>
> Wait means the kernel is waiting for some device i/o command(s) to
> complete.
> The CPU is idle but can't do anything useful without the results from the
> device, probably disk or network.  Starting at 4 am makes the
> 'updatedb'run that
> builds the database for the locate command a likely culprit.  Do you have
> a lot
> of files, slow disks, or perhaps some network mounts that are included?
>
> --
>    Les Mikesell
>     lesmikesell at gmail.com
>
>
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