After a while, apache gets slow without any cause

External Since: Jan 09, 2004 Posts: 4

I've just upgraded our web server to a blazing fast dual Opteron.
With the old machine (a single processor AMD 1800), I never had any
problem related to apache, but the cpu was often too slow to handle
the requests, and we upgraded.

Now. The webserver is fast, very fast. Using top, I can see the load
always under 18%, even in the peak hours. loadavg is always 0.20 or so.

The problem is: apache starts slowing down after 1h/1h:20' of uptime.
Even then loadavg is low, processors are idle, network is not full. It
just slows down. There are no differences between dynamic files or static
ones, pages take minutes to came down (literally), phps or gifs, it's the
same. Connecting via ssh to the server and downloading a gif with the
command: wget http://localhost/img/testimg.gif takes ages to complete.
During this slowdowns, ftp and other services work fine as they should.

If I stop and restart apache, things return fast for another 1h:20'; I
can't understand the cause, the config files are the same used in the old
server. I tried different apache versions, (downgrading to the one used in
the old machine) but the problem persists. I tried changing some critical
value in httpd.config, but the problem remains just the same. I searched
in the error log, raising the log level to "info" but finding nothing
suspect.
Now I done an entry in the root crontab which restarts apache every hour.
Now the site is fast, but this CANNOT be the solution.

Do you have any idea? Can you suggest something to help me find where
the slowdown originates?

This is my config:

Dual Opteron 2400 on Tyan
2Gb RAM
4HD RAID5 (3+1spare) ICP Vortex

Linux 2.4.23 SMP on Debian/GNU unstable
libc6 2.3.2.ds1-10

Apache 1.3.29
mod_gzip (*)

php 4.3.3
turck_mmcache 2.4.5 (*)

Thanks,
S

(*) tried to remove those, but nothing changes.

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External Since: Nov 03, 2003 Posts: 2907

Stefano <c-t-b-k.RemoveThis@gmx.it> wrote:
> Connecting via ssh to the server and downloading a gif with the
> command: wget <a style='text-decoration: underline;' href="http://localhost/img/testimg.gif" target="_blank">http://localhost/img/testimg.gif</a> takes ages to complete.

Whit so less information it's hard to tell what can be the problem.
If you have the status enabled in the server ask the status and check
if there are a lot of request pending or something, check the log
files for unusual things, try to find out if there is a problem is
establishing the connection or a problem in the actual processing.
Check the memory usage and eventually the swap space used.

Davide

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