Upgrade advice moving from Confluence 3.4 to 4.0

Question

We're upgrading Confluence from 3.4 to 4.0 and our DB is hosted on an external MySQL DB server. My preference is to migrate our 3.4 instance to a new server, upgrade that to 4.0 and cut over DNS to point at the 4.0 box. Can I run 3.4 and 4.0 off of the same DB simultaneously or will that cause the world to implode?

Dave Theodore [Coyote Creek Consulting] · Accepted Answer

If you are suggesting pointing two different versions of Confluence at the same database instance, the newer version of Confluence will upgrade the database schema and you will no longer be able to run the old version off of that database.  If bad things happen, then your world begins to implode. :)

You can most likely create a second database instance on your existing database server.  Unless it is already overloaded or low on disk space, there shouldn't any ill effect from doing this.  It would be a good idea to have a different database user for the "dev" instance, though.  This will prevent each version of Confluence from seeing the other's databases.  You'll need to do a mysqldump of the data and load that in the new instance.

If you can't create another instance on the hosted database server, you can install MySQL on a local server, do a mysqldump of the hosted instance data and load your local database with the dump file.  Point your "dev" instance of Confluence to that db and test your upgrade prior to upgrading the live "prod" data.