2 databases
Installation and Configuration
Hello,
Jamroom only uses one (1) database. I'd guess that the smaller database is not being used.
These:
jamroom_cache_rank - 1.5 GB
jamroom_chart_history - 500 MB
jamroom_chart_cache - 494 MB
all have to do with your Song/Video Charts, History, and Ranking, if you don't care to lose that data, you can remove them.
Hope this helps!