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Riak logo
Developer(s) Basho Technologies
Initial release August 17, 2009; 5 years ago (2009-08-17)
Stable release 2.0.0 / September 2, 2014; 5 months ago (2014-09-02)[1]
Development status Active
Written in Erlang
Operating system Linux, BSD, Mac OS X, Solaris
Platform IA-32, x86-64
Type NoSQL database, cloud storage
License Apache License 2.0
Website basho.com/riak/

Riak is a distributed NoSQL key-value data store that offers extremely high availability, fault tolerance, operational simplicity and scalability.[2] In addition to the open-source version, it comes in a supported enterprise version and a cloud storage version that is ideal for cloud computing environments.[3] Riak implements the principles from Amazon's Dynamo paper[4] with heavy influence from Dr. Eric Brewer's CAP Theorem. Written in Erlang, Riak has fault tolerance data replication and automatic data distribution across the cluster for performance and resilience.[5]

Riak CS is an object storage layer that sits on top of the Riak key-value platform. The open source Riak CS can be upgraded to Riak CS Enterprise, the commercial-grade and supported version.[6]

Riak has a pluggable backend for its core storage, with the default storage backend being Bitcask.[7] LevelDB is also supported.

Riak is used by thousands of companies worldwide, including 25% of the Fortune 50.[8] Examples include AT&T, Comcast, UK National Health Services (NHS),[9] and The Weather Channel.[10][11]

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 provides a straightforward REST-ful API through HTTP and Protocol Buffers for basic, PUT, GET, POST, and DELETE functions. Additional query choices are offered including secondary indexes, 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 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 second 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 six hours. In real-time mode,replication to the secondary data center(s) is triggered by updates to the primary data center. All multi-datacenter replication occurs over multiple concurrent TCP connections to maximize performance and network utilization.
Note that multi-datacenter replication is not a part of open source Riak.
Tunable Consistency
Each bucket can be set to be either eventually consistent (to provide high availability) or strongly consistent.

Licensing and support[edit]

Riak is available for free under the Apache 2 License. In addition, Basho Technologies offers two options for its commercial software, Riak Enterprise and Riak Enterprise Plus. Riak Enterprise Plus adds baseline and annual system health checks to ensure long-term platform stability and performance.

Language support[edit]

Riak has official drivers for Ruby, Java, Erlang and Python. There are also numerous community-supported drivers for other programming languages.[12]


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, released September 2, 2014, 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.

See also[edit]


  1. ^ Morrow, Jared (2014-09-02). "[ANN] Riak 2.0.0". Riak users (Mailing list). Retrieved 2014-09-13. 
  2. ^ Harvey, Cynthia (23 May 2014). "60 Open Source Apps You Can Use in the Cloud". Datamation. Retrieved 5 June 2014. 
  3. ^ Harvey, Cynthia (23 May 2014). "60 Open Source Apps You Can Use in the Cloud". Datamation. Retrieved 5 June 2014. 
  4. ^ DeCandia, Giuseppe; Hastorun, Deniz; Jampani, Madan; Kakulapati, Gunavardhan; Lakshman, Avinash; Pilchin, Alex; Sivasubramanian, Swaminathan; Vosshall, Peter; Vogels, Werner (October 14–17, 2007). Dynamo: Amazon’s Highly Available Key-value Store. Proceedings of 21st ACM SIGOPS Symposium on Operating Systems Principles (SOSP '07). Stevenson, Washington, USA: ACM. pp. 205–220. doi:10.1145/1294261.1294281. ISBN 978-1-59593-591-5. Retrieved 5 June 2014. 
  5. ^ Morgan, Timothy Prickett (7 May 2014). "Eucalyptus Scales Out AWS Cloud Clone". Enterprise Tech. Retrieved 5 June 2014. 
  6. ^ Morgan, Timothy Prickett (7 May 2014). "Eucalyptus Scales Out AWS Cloud Clone". Enterprise Tech. Retrieved 5 June 2014. 
  7. ^ "Basho: Bitcask". Retrieved 5 June 2014. 
  8. ^ Novet, Jordan (21 February 2013). "Basho Technologies takes aim at more enterprises with upgrades". GigaOM. Retrieved 5 June 2014. 
  9. ^ Clark, Jack (10 October 2013). "NHS tears out its Oracle Spine in favour of open source". The Register. Retrieved 5 June 2014. 
  10. ^ Henschen, Doug (2 June 2014). "Why Big Data Tools Are Here To Stay: InformationWeek Video". InformationWeek. Retrieved 5 June 2014. 
  11. ^ "Riak Users". Retrieved 5 June 2014. 
  12. ^ "Riak Client Libraries and Community Code". Retrieved 5 June 2014. 

External links[edit]