HOWTO: determine optimal fastcgi settings for Lighttpd
Anyone building a server with a LAMP stack today has tons of options, mine have evolved to using Varnish -> Lighttpd -> Xcache -> PHP5 -> MySQL. Once I had Lighttpd (aka Lighty) installed and running PHP pages I looked to optimize the configuration and push it as hard as possible for more speed. Of course lately I’ve been getting unexplained slowdowns, with many instances of php5-cgi appearing to be taking up almost all of my available CPU on `top`. Reading up on things it appears that I had max_procs, along with PHP_FCGI_CHILDREN, set far too high for the load I’m getting. When you start lighty it gives you the number of processes you’ve define, and then those in turn spawn the number of children you’ve specified. While my settings were too high, they were really overshooting things when you take into account that I’m using Xcache (which provides PHP pre-caching) and Varnish (for HTTP acceleration). So even though one of my dynamic sites that I’m working on to ‘monetize’ things is getting 700-800 hits each day, my caching strategy is taking the load away from the ever available Lighty. Because of this, lighty has much less to do, so giving it a ton of processes to just sit there and eat memory until they’re zombified is a waste. After reading the lighty FAQ and other posts specific to this, I’ve settled on the this for my fastcgi config block within my lighttpd.conf file. (more…)
HOWTO: log the user’s IP, not the proxy’s, in Lighttpd access log
When you run a webserver behind a reverse proxy or HTTP accelerator like Squid or Varnish, the webserver access logs will display the IP of the proxy (generally 127.0.0.1) instead of the end user’s IP. This not only breaks any kind of tracking or reporting you want to run against your webserver logs, but it also takes away a datapoint I’ve had use for in general server admin tasks. This server runs Varnish in front of Lighttpd, and it reveals the end user’s IP in the header as X-Forwarded-For, so it’s just a matter of making Lighttpd (lighty) use that variable in its access logs instead of the default variable defining the referring IP. Once we know that, the configuration is simple; in lighttpd.conf, enter this:
accesslog.format = "%{X-Forwarded-For}i %l %u %t \"%r\" %>s %b /
\"%{Referer}i\" \"%{User-Agent}i\""For the definition of these variables, and plenty more, hit Lighty’s wiki. Props to the poster on the Varnish mailing list for bringing this up and reminding me to fix it! I’ve sent this link to the list so now it’s out there.
Hi, I'm fak3r and I've been online for over 15 years, blogging for 10. I work with open source software, various hardware and whatever else that I can hack on. I enjoy learning by doing, painting infrequently and listening to more music than the law allows. Feel free to follow me and comment on my thoughts and ideas; we're all in it together kid.
