At twitter we’re working on using Cassandra to replace our currents
storage for all tweets. We have a cluster in production that’s being
populated outside the the user-critical path (ie, the cassandra
writing is async).
Additionally, we’re testing and evaluating for basically everything
else in our stack.
We evaluated a lot of things: a custom mysql impl, voldemort, hbase,
mongodb, memcachdb, hypertable, and others.