[lousy_sysadmin]

I've read so many times on HN that people find it hard to scale WordPress. Really? Running WordPress on 128MB VPS and theoretically I can handle more than 250 request per second without problem[1]. Granted that number is just theoretical value but please, if you have gigabytes of RAM and your WordPress site fail after some hundreds of request per second, you certainly have done something terribly wrong. Especially for site with text and very few media content.

Forget any other setup you've ever used, go with this for high performance WordPress

1) Nginx [set so that request to static content to completely bypass PHP]

2) PHP-FPM

3) APC [Object & Database cache]

4) W3 Total Cache or WP Super Cache

5) Varnish

There many other high performance WordPress setup you could find out there but in term of simplicity and manageability, this is the one I fancy most. The bottleneck in this setup is RAM, not PHP, WordPress or MySQL read/write operation as I've seen in many server setup.

Disclaimer : I run small operation of managed WordPress hosting called KittySensei[2]

[1] http://i.imgur.com/m0Dg9YR.png

[2] http://www.kittysensei.com