Long story short, I kind of hosed my MySQL install. It was 5.6.15 I believe. I upgraded it to the current version, 5.6.22. What I think happened was that the installer package (OS X) didn't stop the server before it did it's thing. I didn't bother to stop it because I figured it was smart enough to know to do that. It was not.

But forget about how I got here, I know it was a dumb situation. I don't have comprehensive backups because this is anything but mission critical data. But now that I might lose it, I do kind of want to keep it.

So what I have is my mysql data folder from 5.6.15. And I have a fully functional install of 5.6.22. I tried swapping the data folders but it wouldn't start up. And there was nothing in the system log for errors, besides "status=0" which is not very helpful.

I've had a little help on IRC but not quite enough to be helpful. It was suggested I could start a new server with the old data, and then export it to .sql files, then import that into the new server. But by that logic, couldn't I just start up the new server with the old data and skip the middleman? Is the situation that the old data files I have will ONLY work inside a 5.6.15 installation, and can't/won't work in a 5.6.22 install?

To complicate things further, one of these databases is about 2 TB in size. I can rebuilt it if I have to, but it takes about 2 months to do so, so I'd rather not if I can avoid it.