CentOS - Mar 2011 - Web server becoming unresponsive : high load

Hi,

I have a web server which is randomly becoming unresponsive.   I've checked
for hardware problems with no luck :
- no ethernet errors
- no disk errors
- no memory errors

So far I've managed to point the trouble at the web server since if I
restart httpd (apache) it comes back to normal.

This is not a shared server so I control (or at least like to think of) what
is hosted so I have two suspects:
a) my own code is behaving strangely.   For example, a php script that in a
given situation/parameters increases the usage.
b) some sort of attack.  Either in conjunction to a or other vulnerability.

I am looking for advices in how can I pin point since looking at every line
of code would be infeasible.

Centos 5.5 / apache / php 5.2.10
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
<http://lists.centos.org/pipermail/centos/attachments/20110311/7217d6d8/attachment-0001.html>

On Fri, 11 Mar 2011 14:26:03 -0400
robert mena wrote:
> a) my own code is behaving strangely.   For example, a php script that in a
> given situation/parameters increases the usage.
Log your script's activities to a file with lots of detail.   Got here,
found
this, load is that. If you're concerned about the log getting too huge,
save it to a .bak and re-create it every X minutes.

When it dies, see what the last log entries are.

-- 
MELVILLE THEATRE ~ Melville Sask ~ www.melvilletheatre.com
www.creekfm.com - FIFTY THOUSAND WATTS of POW WOW POWER!

robert mena wrote:
> Hi,
>
> I have a web server which is randomly becoming unresponsive.   I've
> checked for hardware problems with no luck :
> - no ethernet errors
> - no disk errors
> - no memory errors
>
> So far I've managed to point the trouble at the web server since if I
> restart httpd (apache) it comes back to normal.
>
> This is not a shared server so I control (or at least like to think of)
> what is hosted so I have two suspects:
> a) my own code is behaving strangely.   For example, a php script that in
> a given situation/parameters increases the usage.
> b) some sort of attack.  Either in conjunction to a or other
> vulnerability.
You said you've checked for hardware errors, Robert - how 'bout other
errors. For example, when it becomes unresponsive, what's top or free tell
you?

          mark

Robert mena wrote on Fri, 11 Mar 2011 14:26:03 -0400:
> php 5.2.10
upgrade

Kai