[horde] Performance problems with Horde 4

[Ronan SALMON]

Montagutelli Xavier <xavier.montagutelli at unilim.fr> a écrit :

> We face serious performance problems with Horde 4.
>
> Our "old" setup with Horde 3 runs on a Xeon server. On the same  
> hardware, H4 is unusable. The new system is under Debian squeeze,  
> with as many native packages as possible. I have tried both apache2  
> prefork + mod_php5 vs. apache2 worker + php5 fast CGI. MySQL (unix  
> sockets) and memcache are running on the same server. CSS and JS  
> caching is enabled.
>
> One or two minutes after launching apache2, we have "MaxClient"  
> processes (when using prefork, fixed at 300), the four CPUs stays at  
> 100% (mainly user time), the load average increases. H4 sometimes  
> becomes unresponsive, with strange error messages ("no handler for  
> /imp", CSS not delivered, etc.).
>
> Having decreased the PHP parameter max_execution_time (10 s) helps a  
> little bit. MaxRequestsPerChild doesn't change anything. We have  
> tried the apc accelerator. Memcache consumes few memory (~120 MB)  
> despite using the "-m 1024" switch to increase its upper limit.
>
> It looks like PHP is "eating" all the CPU given to it. Something  
> must be wrong in my setup ?? Do someone use H4 with more than 200  
> simultaneous users on the same server ? Do you use Debian or another  
> distro ?
>
> I know it's a bit vague, but I don't understand how to handle this  
> problem. Any help wanted ...

What auth/pref/imap backends are you using ?
Did you customize some prefs ?

Ronan.