This site was setup in 2007 with Drupal 5, and it has not been upgraded until today. I did not feel the need to upgrade since this is just a personal blog. A few days ago I wanted to install a module, but Drupal version 6 is required, so I thought it's finally the time to upgrade Drupal. This Drupal upgrade tutorial suggests to first take down the site to upgrade, but I do not like that. It turns out that more than a few days of work are required to bring back a fully functional upgraded site, so taking the site down to upgrade is not a good idea. Below is what I did to upgrade this site from version 5.3 to 6.22 with almost zero down time (well, maybe a few seconds, I didn't time it).