Dynamo is a set of techniques that together can form a highly available key-value structured storage system or a distributed data store. It has properties of both

database In computing, a database is an organized collection of data or a type of data store based on the use of a database management system (DBMS), the software that interacts with end users, applications, and the database itself to capture and a ...

s and

distributed hash table A distributed hash table (DHT) is a Distributed computing, distributed system that provides a lookup service similar to a hash table. Key–value pairs are stored in a DHT, and any participating node (networking), node can efficiently retrieve the ...

s (DHTs). It was created to help address some scalability issues that

Amazon Amazon most often refers to: * Amazon River, in South America * Amazon rainforest, a rainforest covering most of the Amazon basin * Amazon (company), an American multinational technology company * Amazons, a tribe of female warriors in Greek myth ...

experienced during the holiday season of 2004.Amazon Takes Another Pass at NoSQL with DynamoDB
/ref> By 2007, it was used in

Amazon Web Services Amazon Web Services, Inc. (AWS) is a subsidiary of Amazon.com, Amazon that provides Software as a service, on-demand cloud computing computing platform, platforms and Application programming interface, APIs to individuals, companies, and gover ...

, such as its Simple Storage Service (S3).

Relationship to DynamoDB

Amazon DynamoDB is "built on the principles of Dynamo" and is a hosted service within the AWS infrastructure. However, while Dynamo is based on leaderless replication, DynamoDB uses single-leader replication.

Principles

* Incremental scalability: Dynamo should be able to scale out one storage host (or “node”) at a time, with minimal impact on both operators of the system and the system itself. * Symmetry: Every node in Dynamo should have the same set of responsibilities as its peers; there should be no distinguished node or nodes that take special roles or extra set of responsibilities. * Decentralization: An extension of symmetry, the design should favor decentralized peer-to-peer techniques over centralized control. * Heterogeneity: The system should be able to exploit heterogeneity in the infrastructure it runs on. For example, the work distribution must be proportional to the capabilities of the individual servers. This is essential in adding new nodes with higher capacity without having to upgrade all hosts at once.

Techniques

Implementations

Amazon published the paper on Dynamo, but never released its implementation. The index layer of Amazon S3 implements and extends many core features of Dynamo. Since then, several implementations have been created based on the paper. The paper also inspired many other

NoSQL NoSQL (originally meaning "Not only SQL" or "non-relational") refers to a type of database design that stores and retrieves data differently from the traditional table-based structure of relational databases. Unlike relational databases, which ...

database implementations, such as Apache Cassandra, Project Voldemort and Riak.

References

External links