How to migrate old redmine server to a new one upgrading version and changing DB engine

Question

I am planning to migrate my Redmine (1.0.5) to a new machine. I would like to upgrade Redmine to latest version and change the database from MySQL to Postgresql with this migration.

My plan A is:

1. move Redmine 1.0.5 to new machine with database
2. upgrade Redmine 1.0.5 to latest version
3. migrate database from MySQL to Postgresql

plan B:

1. upgrade Redmine 1.0.5 to latest version
2. migrate database from MySQL@MachineOld to Postgresql@MachineOld
3. move database to new Machine
4. move Redmine to new machine

plan C:

1. migrate database from MySQL@old machine to Postgresql@new machine
2. install latest Redmine on new machine with migrated db (1.0.5) and do database migration (1.0.5 -> latest)

There are many possible ways to do this job. Which way do you recommend? After step 0: make a good backup.

Solution 1

I plan do upgrading with following plan.

Backup and practice on virtualbox before do any change

I use no plugins in my old redmine.

Read install guild and upgrade guild.

* [Redmine Instal Guild](http://www.redmine.org/projects/redmine/wiki/RedmineInstall)
* [Redmine Upgrade Guild](http://www.redmine.org/projects/redmine/wiki/RedmineUpgrade)

Using taps to convert/transfer database.

  * http://adam.heroku.com/past/2009/2/11/taps_for_easy_database_transfers/
  * https://github.com/ricardochimal/taps
  * http://www.redmine.org/boards/2/topics/12825

Possible issues:

1. UTF8 issue:

   issue #39 issue #110 with encoding=UTF8 in taps will solve problem. [comment @ issue #39] and comment @ issue #110

2. RACK dependency issue(Unable to fetch tables...):

   install rack 1.0.1

   Check issue #128 for information. (this comment)

Follow install guild and upgrade guild

1. install requirements
2. setup configurations
3. do db:migrate
4. test with WEBRICK
5. setup production server

After hours studying and trail, I upgrade redmine to new machine with latest version and migrate my database.

Note: Due to reputation limitation, some links are removed or using pre tag surrounded.

Solution 2

Plan C sounds safest to me. With that plan, you can leave the original instance untouched while sorting out issues on the new server.

Be mindful of plugins, too. It's likely that you'll find incompatible ones with that big of a version jump.

I've been pondering the same migration myself, but have been putting it off for a while. I know for a fact that some of the plugins I use in 1.2 are no longer supported in 2.x.