BigTable vs DynamoDB

DynamoDB BigTable
Architecture Decentralized
Every node has same set of responsibilites		 Centralized
Master handles metadata, tablet server handle reads/writes
DataModel Key-Value Multidimensional Sorted-Map
Partitioning Consistent Hashing
Each node is assigned to a random position on the ring		 Tablets
Each table is broken into a contiguous range of rows called tablets
Replication Sloppy Quorum
Each data item is replicated to 'N' number of nodes		 GFS Chunk replication
Data is stored in GFS. Files in GFS are broken into chunks, and these chunks are replicated to different servers
CAP AP CP
Operations By Key By Key-Range
Storage Plug-in SSTables in GFS
Memberships and failure detection Gossip based protocol Handshakes initiated by the master

Cassandra is a distributed, decentralized, and highly available NoSQL database. Its architecture is based on Dynamo and BigTable. Cassandra can be described as a BigTable-like datastore running on a Dynamo-like infrastructure. Cassandra is also a wide-column store and utilizes the storage model of BigTable, i.e., SSTables and MemTables.