Hazelcast IMDG – open-source distributed in-memory data store and computation platform

Hazelcast IMDG (Hazelcast) is an open-source distributed in-memory data store and computation platform supporting a wide variety of data structures such as Map, Set, List, MultiMap, RingBuffer, and HyperLogLog. Hazelcast is designed to be lightweight and easy to use.

Hazelcast provides a wide variety of distributed data structures and concurrency primitives, including:

  • a distributed, partitioned and queryable in-memory key-value store implementation, called IMap.
  • additional data structures and simple messaging constructs such as Set, MultiMap, Queue, Topic.
  • cluster-wide unique ID generator, called FlakeIdGenerator.
  • a distributed, CRDT based counter, called PNCounter.
  • a cardinality estimator based on HyperLogLog.

Additionally, Hazelcast includes a production-ready Raft implementation which allows implementation of linearizable constructs such as:

  • a distributed and reentrant lock implementation, called FencedLock
    primitives for distributed computing such as AtomicLong, AtomicReference and CountDownLatch.

Hazelcast data structures are in-memory, highly optimized and offer very low latencies. For a single get or put operation on an IMap, you can typically expect a round-trip-time of under 100 microseconds.

Hazelcast automatically replicates data across the cluster and you are able to seamlessly tolerate failures and add additional capacity to the cluster when needed.

It is implemented in Java language and has clients for Java, C++, .NET, REST, Python, Go and Node.js. Hazelcast IMDG also speaks Memcached and REST protocols. It plugs into Hibernate and can easily be used with any existing database system.

Hazelcast also has first-class support for running on different cloud providers such as AWS, GCP and Azure as well as on Kubernetes.

You can extend Hazelcast IMDG’s functionality by using its plugins.

Features include:

  • Stores everything in-memory (RAM). It is designed to perform fast reads and updates.
  • Peer-to-peer; there is no single point of failure in a Hazelcast IMDG cluster; each member in the cluster is configured to be functionally the same. They all store equal amounts of data and do equal amounts of processing. Embed Hazelcast IMDG in your existing application or use it in client and server mode where your application is a client to Hazelcast members.
  • When the size of your memory and compute requirements increase, new members can be dynamically joined to the Hazelcast IMDG cluster to scale elastically.
  • Data is resilient to member failure. Data backups are distributed across the cluster. This is a big benefit when a member in the cluster crashes as data is not lost. Hazelcast keeps the backup of each data entry on multiple members. On a member failure, the data is restored from the backup and the cluster continues to operate without downtime.
  • Members are always aware of each other unlike in traditional key-value caching solutions.
  • Build your own custom-distributed data structures using the Service Programming Interface (SPI) if you are not happy with the data structures provided.
  • Provides out-of-the-box distributed data structures.

Support: Documentation, GitHub Code Repository
Developer: Hazelcast, Inc.
License: Apache License 2.0

Hazelcast is written in Java. Learn Java with our recommended free books and free tutorials.

Return to Caching Systems

Popular series
Free and Open Source SoftwareThe largest compilation of the best free and open source software in the universe. Each article is supplied with a legendary ratings chart helping you to make informed decisions.
ReviewsHundreds of in-depth reviews offering our unbiased and expert opinion on software. We offer helpful and impartial information.
Alternatives to Proprietary SoftwareReplace proprietary software with open source alternatives: Google, Microsoft, Apple, Adobe, IBM, Autodesk, Oracle, Atlassian, Corel, Cisco, Intuit, and SAS.
GamesAwesome Free Linux Games Tools showcases a series of tools that making gaming on Linux a more pleasurable experience. This is a new series.
Artificial intelligence iconMachine Learning explores practical applications of machine learning and deep learning from a Linux perspective. We've written reviews of more than 40 self-hosted apps. All are free and open source.
Guide to LinuxNew to Linux? Read our Linux for Starters series. We start right at the basics and teach you everything you need to know to get started with Linux.
Alternatives to popular CLI tools showcases essential tools that are modern replacements for core Linux utilities.
System ToolsEssential Linux system tools focuses on small, indispensable utilities, useful for system administrators as well as regular users.
ProductivityLinux utilities to maximise your productivity. Small, indispensable tools, useful for anyone running a Linux machine.
AudioSurveys popular streaming services from a Linux perspective: Amazon Music Unlimited, Myuzi, Spotify, Deezer, Tidal.
Saving Money with LinuxSaving Money with Linux looks at how you can reduce your energy bills running Linux.
Home ComputersHome computers became commonplace in the 1980s. Emulate home computers including the Commodore 64, Amiga, Atari ST, ZX81, Amstrad CPC, and ZX Spectrum.
Now and ThenNow and Then examines how promising open source software fared over the years. It can be a bumpy ride.
Linux at HomeLinux at Home looks at a range of home activities where Linux can play its part, making the most of our time at home, keeping active and engaged.
Linux CandyLinux Candy reveals the lighter side of Linux. Have some fun and escape from the daily drudgery.
DockerGetting Started with Docker helps you master Docker, a set of platform as a service products that delivers software in packages called containers.
Android AppsBest Free Android Apps. We showcase free Android apps that are definitely worth downloading. There's a strict eligibility criteria for inclusion in this series.
Programming BooksThese best free books accelerate your learning of every programming language. Learn a new language today!
Programming TutorialsThese free tutorials offer the perfect tonic to our free programming books series.
Linux Around The WorldLinux Around The World showcases usergroups that are relevant to Linux enthusiasts. Great ways to meet up with fellow enthusiasts.
Stars and StripesStars and Stripes is an occasional series looking at the impact of Linux in the USA.
Notify of

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Inline Feedbacks
View all comments