FastCGI is a high-performance extension to CGI. It is suitable for production environments, and is the
standard method for deploying Catalyst in shared hosting environments.
ProsSpeed
FastCGI performs equally as well as mod_perl. Don't let the 'CGI' fool you; your app runs as multiple
persistent processes ready to receive connections from the web server.
AppServer
When using external FastCGI servers, your application runs as a standalone application server. It may be
restarted independently from the web server. This allows for a more robust environment and faster reload
times when pushing new app changes. The frontend server can even be configured to display a friendly
"down for maintenance" page while the application is restarting.
Load-balancing
You can launch your application on multiple backend servers and allow the frontend web server to perform
load-balancing among all of them. And of course, if one goes down, your app continues to run.
Multipleversionsofthesameapp
Each FastCGI application is a separate process, so you can run different versions of the same app on a
single server.
CanrunwiththreadedApache
Since your app is not running inside of Apache, the faster mpm_worker module can be used without worrying
about the thread safety of your application.
Widelysupported.
FastCGI is compatible with many server implementations, not just Apache.
Cons
You may have to disable mod_deflate. If you experience page hangs with mod_fastcgi then remove
deflate.load and deflate.conf from mods-enabled/
Morecomplexenvironment
With FastCGI, there are more things to monitor and more processes running than when using mod_perl.
StandaloneFastCGIServer
In server mode the application runs as a standalone server and accepts connections from a web server.
The application can be on the same machine as the web server, on a remote machine, or even on multiple
remote machines. Advantages of this method include running the Catalyst application as a different user
than the web server, and the ability to set up a scalable server farm.
To start your application in server mode, install the FCGI::ProcManager module and then use the included
fastcgi.pl script.
$ script/myapp_fastcgi.pl -l /tmp/myapp.socket -n 5
Command line options for fastcgi.pl include:
-d -daemon Daemonize the server.
-p -pidfile Write a pidfile with the pid of the process manager.
-l -listen Listen on a socket path, hostname:port, or :port.
-n -nproc The number of processes started to handle requests.
See below for the specific web server configurations for using the external server.