As part of the process of upgrading Canvas to support newer technologies, specifically Rails 3, Instructure will no longer be supporting MySQL as a database backend for Canvas beginning with the July 12, 2014 stable release. There are no known major issues with MySQL with Canvas running on Rails 2, but as soon as Rails 2 support is dropped in favor of Rails 3, there are many tests that do not pass, and it is suggested that any production Canvas environments migrate to PostgreSQL by July 12.
If anyone would like assistance with the migration, please post a separate topic to the group, or to the IRC channel ##canvas-lms on Freenode.
While Instructure will no longer directly support MySQL, we will continue to accept community contributions that are specifically for MySQL fixes if anyone would like to continue to maintain it for their own purposes. These contributions will undergo the same code review process by Instructure engineers that any other community contribution undergoes.