Most of our hardcore data is in non-relational sources (including Hadoop). Our global DB is Postgres - that holds everything which we haven't had a reason to m

Most of our hardcore data is in non-relational sources (including Hadoop). Our global DB is Postgres - that holds everything which we haven't had a reason to move off it - it's a pair of Sun boxes with 128GB of RAM using Postgres warm standby (in this case the hardware is a lot cheaper than trying to shard it). And we also have a ton of other MySQL and Postgres databases running other services.