Server support blog

I’ve been running PHP in fastcgi mode with suExec for some time on about 50+ servers with different workload and various content. There are some tips and tricks that can improve the performance and increase the stability of such configuration.

• I found that in some situation – under extremely heavy load Apache2 worker MPM is not as stable as prefork – server process is crashing without and reasonable explanation in the logs. for such situations it’s better to switch back to prefork MPM by commenting out HTTPD variable in /etc/sysconfig/httpd and restarting apache (via [cci lang=”bash”]service httpd restart[/cci])
• mod_fcgid can use some additional tuning for performance/slow scripts -YMMV. What I have now in the 00-fcgid.conf is below
  Apache

  LoadModule fcgid_module modules/mod_fcgid.so <IfModule mod_fcgid.c> ProcessLifeTime 300 IPCCommTimeout 120 IPCConnectTimeout 120 MaxProcessCount 1500 DefaultMaxClassProcessCount 1500 DefaultMinClassProcessCount 0 # Sane place to put sockets and shared memory file SocketPath run/mod_fcgid SharememPath run/mod_fcgid/fcgid_shm #php suexec only PHP_Fix_Pathinfo_Enable 1 AddType application/x-httpd-php .php AddHandler php-fcgi .php Action php-fcgi /fcgi-bin/php-fcgi FCGIWrapper /var/www/cgi-bin/php-fcgi .php Alias /fcgi-bin/ /var/www/cgi-bin/ <Location /fcgi-bin/> SetHandler fcgid-script Options +ExecCGI </Location> DirectoryIndex index.php </IfModule>

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  LoadModule fcgid_module modules/mod_fcgid.so   <IfModule mod_fcgid.c>     ProcessLifeTime 300     IPCCommTimeout 120     IPCConnectTimeout 120     MaxProcessCount 1500     DefaultMaxClassProcessCount 1500     DefaultMinClassProcessCount 0   # Sane place to put sockets and shared memory file SocketPath run/mod_fcgid SharememPath run/mod_fcgid/fcgid_shm #php suexec only     PHP_Fix_Pathinfo_Enable 1     AddType application/x-httpd-php .php     AddHandler php-fcgi .php     Action php-fcgi /fcgi-bin/php-fcgi     FCGIWrapper /var/www/cgi-bin/php-fcgi .php     Alias /fcgi-bin/ /var/www/cgi-bin/     <Location /fcgi-bin/>         SetHandler fcgid-script         Options +ExecCGI     </Location>     DirectoryIndex index.php </IfModule>

  For more in-depth parameter description please refer to this [amazon_link id=”6132769471″ target=”_blank” ]FastCGI[/amazon_link] book

• If you are running high traffic server ( I am talking about 200 000+ visitors/day) you might need to adjust php-cgi wrapper configuration to something like this.
  Shell

  ... export PHP_FCGI_MAX_REQUESTS=5000 export PHP_FCGI_CHILDREN=1 exec /usr/bin/php-cgi

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  ... export PHP_FCGI_MAX_REQUESTS=5000 export PHP_FCGI_CHILDREN=1 exec /usr/bin/php-cgi

• If you were using [cci lang=”php”]$_SERVER[‘REMOTE_USER’][/cc] in your PHP scripts, you will have to start using [cci lang=”php”]$_SERVER[‘REDIRECTED_REMOTE_USER’][/cc] instead (same goes for REMOTE_SERVER).
• If you are using “stock” Centos5 php 5.1.6 then you will have to change wrapper variable [cci lang=”bash”]PHP_FCGI_CHILDREN=0[/cc] to [cci lang=”bash”]PHP_FCGI_CHILDREN=1[/cc] otherwise php-cgi will just refuse to start (corrected in php 5.2.x I think)

This gives some additional details on the configuration that is worth further investigation. I hope it will be helpful.