To be perhaps overly detailed: Hbase is an open source approximation of bigtable. Bigtable _uses_ leveldb as its per-shard local storage mechanism; Rocks is a c

To be perhaps overly detailed: Hbase is an open source approximation of bigtable. Bigtable _uses_ leveldb as its per-shard local storage mechanism; Rocks is a clone+extension of leveldb. Bigtable and hbase are higher level and provide functionality across shards and machines. Level and rocks are building blocks that provide a log-structured merge tree storage and retrieval mechanism.