I'm planning to upgrade the OS of the servers this coming Wednesday.I would like to take a full day of outage (hoping for it to be only a few hours). This would upgrade the OS on the main server from Ubuntu 12.04 to 16.04 and all other servers from Ubuntu 14.04 to 16.04. Please let me know ASAP if this would not work for your project.
UPDATE
The upgrade is completed and all systems are back up and running. Please email opensource@ncsa.illinois.edu if anything does not work as expected and I will look at it ASAP. The following problems were part of the blame for longer than expected outage.
During this upgrade we had some trouble with one of the plugins in confluence (that was not being used) and has been removed. I might contact some of you later with questions about some of the other plugins to see if we can disable some of those plugins in the hope that this will cause less trouble in the future and will make confluence a little faster.
A second problem during this upgrade an unexpected problem with Bitbucket appeared. Bitbucket does not support MySQL 5.7 which happens to be the default version in Ubuntu 16.04. To overcome this I have migrated the database for Bitbucket to PostgreSQL instead of MySQL. I might migrate over time others (FishEye and Crowd) to PostgreSQL as well to have a consistent set of databases. Both JIRA and Confluence are already using PostgreSQL.