Apache webserver outage - [real info this time]

[Bob Brennan]

On 4/13/05, Bob Brennan <rbrennan96 at gmail.com> wrote:
> I have a server which went completely unresponsive today on port 80
> for 20 minutes and would appreciate any pointers as to what might have
> happened.
> 
> A bit of background:
> * FC3, Up2Date
> * The Apache webserver serves a dozen virtual websites
> * Sendmail + Dovecot + Squirrelmail for all sites
> * Spamassasin recently activated (yesterday)
> 
> The problem + observations:
> * All websites were inaccessible from 14:00 gmt to 14:20 today
> * The mailserver was running and responsive during that time
> * FTP was running and responsive during that time
> * telnet theServer.com 80 timed out with no connection during that time
> 
> What I checked:
> * all access_log and error_log for all sites - showed 5 users using
> the sites at the time but nothing unusual
> * no evidence of a DOS attack (that I could see)
> * no records of anything unusual in system logs
> * no accesses or errors in any of the http logs during that time
> 
> Thankfully the webserver came back as if by magic after 20 minutes and
> was immediately responsive.
> 
> Any insights into anything else I can check? Needless to say an
> embarassing incident for a webmaster who whould like to prevent it
> happening again.
> 
> Thanks in advance,
> bob

It's happened again, only this time I can pinpoint the cause. I was
remotely administering another problem using Webmin on Firefox on XP,
using the Command window. I wanted to see active services so I entered
"service --status-all" which normally ouputs several screenfulls of
information. Not only did Webmin fail to return the reply but all http
services stopped again. Curiously when I minimised Firefox it also
froze with only a blinking icon and had to be ctrl-alt-deleted out of.
The http server was then offline for at least 20 minutes before it
recovered.

The last incident I can also tie to Squirrelmail and some intensive
(buggy) HTML plug-in editing. This also caused Firefox to need to be
killed.

So my question has changed - obviously there are resource-hogging
issues to do with Webmin, Squirrelmail, and apparently Firefox; but
how do I configure Apache to stop these hogs from taking down my
entire http service for 20 minutes at a time?

Thanks in advance for any advice,
bob