For the past 12 months OzBargain has been running on a single Linode 720 at Linode, in their Fremont data centre. I thought it was pretty good for a Drupal website getting 5 million page views per month, especially renting that VPS is pretty much free to me :) Due to surge in traffic as end of financial year draws close, it has been struggling though. Loadavg will go over 1 regularly during day time, and can peak at 3-4 in evening hours. It was so bad at one stage that Nginx would stop serving FastCGI requests.
So I went and got another Linode 720 at Fremont running Ubuntu 10.04 LTS, and migrated the database (~700MB so far) at 1:30am yesterday morning. There was around 10 minutes of downtime for me to copy the database around and reconfigure the files. And now OzBargain is running on two $39.95/month servers, one running Nginx + PHP-FastCGI, and the other running MySQL. Here's the loadavg of the web server (taken from Cacti)
Note the big drop of load on the 12th. Two are indeed better than one :)
Looking at hitting 6 million page views this month and I know everything is going to die down a bit until around October/November. Let's see how long this setup will last.