Re: [Pound Mailing List] Performance problems with debian sarge version of pound (1.8.2)

On Wed, 2006-05-03 at 10:47 +0200, Bernhard Grün wrote:
> Helle there,
> 
> My name is Bernhard Grün, I am from Germany and I am one of the
> administrators of http://www.gesichterparty.de/ . This is a quite
> large party community site that runs pound to balance the web traffic
> across backend servers (3 backends at the moment). In average we have
> about 700 requests per second. Pound is already on its own dedicated
> server (Pentium D 805, 1 GB of RAM)
> Now the problem is that we can't use pound to log the requests anymore
> because the load would go to values as high as 10. Without logs we
> have values up to 2.
> Now the question is how can we optimize pound to use logging again?
> Is Pound 2.0.4 faster in that manner? Or should we try to compile
> Pound by ourselfs to get a bit more performance?
> As logging backend we use syslog-ng on the same machine as pound
> resides. It does not need much cpu power in our configuration (about
> 5-10%) but has to write about 6 to 8 GB of logs in 24 hours.
> By the way: we can't use the backend servers to do the logging because
> this makes some problems when we try to analyze our logs with awstats.
> 
> I really really hope that someone of you has a quite nice idea to help us.

Several answers here:

- Pound 2.0.4 with PCRE is significantly faster and more efficient than
older versions. This means less CPU load for the same workload, which
may help in your case.

- syslog is normally limited by disk rather than CPU (at least in my
experience). You should look at tuning options (such as not flushing the
output on every message - big win), better/faster disk access (HW) and
possibly remote logging (if you have some other disk-intensive
application on the same machine).

- you can very well run Pound without syslog - compile it to send
messages to stdout/stderr. A package like the DJB daemontools is very
helpful for these cases, and may help quite a bit with performance.

- finally you could reconsider back-end logs: Pound passes the original
client IP address in the X-Forwarded-for header, which could be logged
by your back-ends and later used by awstats.

Hope this helps some.
-- 
Robert Segall
Apsis GmbH
Postfach, Uetikon am See, CH-8707
Tel: +41-44-920 4904


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http://www.apsis.ch/pound/pound_list/archive/2006/2006-05/1146646072000/1146761480000