I upgraded our Moodle 1.9 site to version 2.1 today on our Debian HyperV server. The process went rather poorly compared to my test upgrades in the spring. In May, I copied our entire site to a different server and upgraded it to 2.0 without difficulty. This time, I ran into more issues but got there by the end of the day. I gather this was largely due to changes in the installer itself from version 2.0 to 2.1.
Converting the database engine to INNODB as suggested slowed performance way down, and changing database collation to utf8_general_ci led to “mixed collation” database errors during upgrade, and I had more success with the original MYISAM engine and utf8_unicode_ci collation. I will need to find out how important those settings are to long-term site performance.
With these problems solved, the upgrade script could actually run. The first time through, it failed partway through, and the course files did not get converted. This caused all file links to break, so delete database, delete data directory, duplicate old site, and try again! It went smoothly the next time. Apparently, Moodle has changed the way it stores uploaded files and had to reshuffle all of the existing files to fit.
I am not so pleased with Moodle theme choices. My two favorite potential site themes so far are Accentuate and Créatif, but I wish I had more good choices. Do you have any? I may just install a few themes on the site and add Theme Selector so that people can make their own choices. It will be interesting to see whether the benefits of customization outweigh the potential confusion caused by people seeing so many different Moodle looks. Currently, our pages are very recognizable.
After I activate our new Google Apps domain, I will install the Google-Moodle integration plug-in and activate the Google Apps repository so that users may use the file picker to select Apps documents. Then it will be time to rewrite the assignment calendar plug-ins for Moodle 2.0 (or convince the school to adopt a commercial solution!).