I'm not so sure if SDB is implemented in Erlang.

Check out http://www.allthingsdistributed.com/2007/10/amazons_dynamo.h...

It says:

"In Dynamo, each storage node has three main software components: request coordination, membership and failure detection, and a local persistence engine. All these components are implemented in Java."

"Engines that are in use are Berkeley Database (BDB) Transactional Data Store, BDB Java Edition, MySQL, and an in-memory buffer with persistent backing store."

"All communications are implemented using Java NIO channels. "

I doubt they wrote Dynamo in Java and then converted the whole thing to Erlang.

Also, Erlang does not fit in the 'eventual consistency' and 'failure is an option' model that Amazon like to promote.