Almost all of the above. Because my company ships an appliance, we've got Postgres, Tokyo, Redis and several other semi-databases (Judy, Memcached, etc) on the

Almost all of the above. Because my company ships an appliance, we've got Postgres, Tokyo, Redis and several other semi-databases (Judy, Memcached, etc) on the appliances, and Postgres, Couch and HDFS/HBase on our side. Much of the reason for the large number is for legacy code that is quickly being replaced. We're settling into Postgres, Redis and Couch.