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Developer(s) Basho Technologies
Initial release 2009
Stable release 1.4 / July 10, 2013 (2013-07-10)
Development status Active
Written in Erlang, C, C++, some JavaScript
Operating system Linux, BSD, Mac OS X, Solaris
Platform IA-32, x86-64
Type Database
License Apache License 2.0
Website basho.com/riak/

Riak[1] is an open-source, fault-tolerant key-value NoSQL database implementing the principles from Amazon's Dynamo paper[2] with heavy influence from Dr. Eric Brewer's CAP Theorem. Written in Erlang, Riak is known for its ability to distribute data across nodes using consistent hashing in a simple key/value scheme in namespaces called buckets.

Riak has a pluggable backend for its core shard-partitioned storage, with the default storage backend being Bitcask,[3] LevelDB is also supported.

Riak is used by thousands of companies worldwide, including over 25% of the Fortune 50.[4] Examples include AT&T, AOL, Ask.com, Best Buy, Boeing, Bump, Braintree, Comcast, DataPipe, Gilt Group, UK National Health Services (NHS),[5] OpenX, Rovio,[6] Symantec, TBS, The Weather Channel, WorkDay, Voxer, Yahoo! Japan, Yandex, and many more.[7] According to the DB-Engines ranking, Riak is one of the most popular key-value stores.[8]

Main Features[edit]

Fault-Tolerant Availability
Riak replicates key/value stores across a cluster of nodes with a default n_val of three. In the case of node outages due to network partition or hardware failures, data can still be written to a neighboring node beyond the initial three, and read-back due to its "masterless" peer-to-peer architecture.
Riak supports a REST API through HTTP and Protocol Buffers for basic PUT, GET, POST, and DELETE functions. Additional query choices are offered including secondary indices, Riak Search leveraging the Apache Solr Engine with Solr client query APIs and MapReduce. MapReduce has native support for both JavaScript (using the SpiderMonkey runtime) and Erlang.
Predictable Latency
Riak evenly distributes data across nodes with consistent hashing and can provide an excellent latency profile, even in the case of multiple node failures. Key/Values can be stored in memory, disk, or a combination depending on which pluggable backend one chooses.
Multi-Datacenter Replication
In multi-datacenter replication, one cluster acts as a "primary cluster". The primary cluster handles replication requests from one or more "secondary clusters" (generally located in other regions or countries). If the datacenter with the primary cluster goes down, a secondary cluster can take over as the primary cluster.
There are two primary modes of operation: fullsync and realtime. In fullsync mode, a complete synchronization occurs between primary and secondary cluster(s), by default every 360 minutes. In realtime mode, continual, incremental synchronization occurs - replication is triggered by new updates.

Licensing and Support[edit]

Riak is available for free under the Apache 2 License. In addition, Basho Technologies offers commercial licenses with subscription support and the ability for MDC (Multi Data Center) Replication.

Language Support[edit]

Riak has official drivers for Ruby, Java, Erlang, Python, PHP, and C/C++. There are also a numerous amount of community-supported drivers for other programming languages and frameworks.[9]


Riak was developed at Basho Technologies to initially power a web Sales Force Automation application by former engineers and executives from Akamai. There was more interest in the datastore technology than the applications built on it, so the company decided to build a business around Riak itself, gaining adoption throughout the Fortune 100 and becoming a foundation to many of the world’s fastest-growing Web-based, mobile and social networking applications, as well as cloud service providers. Releases after graduation include

  • 1.1, released Feb 21 2012, added Riaknostic, enhanced error logging and reporting, improved resiliency for large clusters, and a new graphical operations and monitoring interface called Riak Control.
  • 1.4, released July 10, 2013, added counters, secondary indexing improvements, reduced object storage overhead, handoff progress reporting, and enhancements to MDC replication.
  • 2.0, technical preview released October 29, 2013, added new data types including sets, maps, registers, and flags simplifying application development. Strong consistency by bucket, full-text integration with Apache Solr, Security, and reduced replicas for Secondary sites.

The back-end system of the Whisper (app) messaging system originally used Riak, but after major performance and scaling problems the system was converted to use MySQL.[10]

See also[edit]


External links[edit]