high disk i/o after every one hour for 25 minutes.

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listedin
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Joined: 2015/11/06 09:41:00

high disk i/o after every one hour for 25 minutes.

Post by listedin » 2015/11/06 09:44:09

hi,

i am new to centos. we have a fujitsu based server with centos 5.9.
we hear high disk noise every one hour for 25 minutes all the times. when i check system informations in webmin. it shows high disk i/o.
what is causing that?

thank you :cry:

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TrevorH
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Posts: 33202
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: high disk i/o after every one hour for 25 minutes.

Post by TrevorH » 2015/11/06 09:55:32

I have moved your post from the CentOS 7 forums to the CentOS 5 ones since you appear to be using that.

I would suggest that you check /var/log/cron to see what is started by cron at around the time of the problem.

Also, you should not be running 5.9 as it is several years old and has unfixed security vulnerabilities. If you run yum update then you will be brought up to the current level which is 5.11 plus the latest fixes. You can see details of the fixes made between the 2 versions on http://rhn.redhat.com/errata/rhel-server-errata.html - CentOS 5.9 came out in September 2013 so look at anything since then to see what you may be missing.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

listedin
Posts: 2
Joined: 2015/11/06 09:41:00

Re: high disk i/o after every one hour for 25 minutes.

Post by listedin » 2015/11/06 12:14:14

ok i had a look at /var/log/cron and found nothing unusual.

we are running mrtg for snmp graphing and cron log file has only mrtg jobs. those jobs run every 5 minute. but disk IO becomes high only at the start of an hour.

the cron log file i had a look at has only root jobs.. but when i view scheduled jobs over webmin. it shows many other jobs at hourly, daily and weekly interval.

i have disabled all daily jobs for testing from webmin but no effect.

how should i find out whats causing high IO at specific time duration. help

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TrevorH
Site Admin
Posts: 33202
Joined: 2009/09/24 10:40:56
Location: Brighton, UK

Re: high disk i/o after every one hour for 25 minutes.

Post by TrevorH » 2015/11/06 15:20:04

Logon to the system and run top and watch the processes in use on the system at the time it is happening.
The future appears to be RHEL or Debian. I think I'm going Debian.
Info for USB installs on http://wiki.centos.org/HowTos/InstallFromUSBkey
CentOS 5 and 6 are deadest, do not use them.
Use the FAQ Luke

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