Many plug-ins have been written to allow a person to migrate from other issue tracking systems to Redmine. In these casese, the assumption is that the company is discarding an old issue tracking system and starting with a new Redmine installation. Ours is a different scenario. Our group is already using Rackspace. And we were merging with a group that had their own installation of the software. So what I needed to be able to do was merge the two databases together.
The ‘new’ team had two projects in their system, only one of which was of interest to us. That project already existed in our system. A number of users overlapped in the two systems. And the ‘new’ team’s system included some Redmine plugins that we weren’t using. The last one proved to be the most difficult to deal with.
The integration of the wiki into ours was very straightforward. What proved to be difficult was the issues. Using the existing ‘merge’ plug-ins as templates, as well as my knowledge from having created a limited interface (for our clients to see their issues, but not everything in the system), I was able to figure out most of the entries that needed to be moved over.
The easiest method of combining the issues into our system proved to be getting a csv extract from the ‘new’ system, parsing that, and adding it in. Unfortunately, doing it that way, we missed out on any attachments as well as any update history for the issues.

I download the scritps and i cant unzip them, gave a error can you send me by email? thanks.
I must have lost the zip file with the migration of this site awhile back. I will try to dig them out of my old files this weekend.
Note, however, that this is for an old version of Redmine, so you may need to tweak them a bit.
Most than the script i need some method or some process to do this, i have two redmine databases and i need to merge them into one redmine instance, and all data must be merge and redmine must work normally with all the data, but primary keys and etc things, makes me crazy, so i try the holly plugins of rake but do not work.
In a way i’m on fire, thanks for your help! 😀
I finally found the backup of this file. The link is now working.
admin: i’ve downloaded the scripts, i have (for now) one question about these perls script:
These script, works for any redmine version? Or for a specifically version? I will try it in a moment but i just want now, for which redmine versions, works.
They worked when I wrote them several years ago. I’d suggest making a quick check of the tables to ensure the columns haven’t changed.