I work at Nokia and I'm not aware of any big production uses of it inside Nokia. Most of the teams in my part of the company use Hadoop.

Oh well.

Actually the largest MapReduce cluster at Nokia runs Disco. Feel free to contact me at ville.h.tuulos at nokia dot com if you want to give it a try.

It seems to be a very active project:

https://github.com/tuulos/disco/commits/master