Hazelcast IMDG

WAN Replication

Feature of IMDG Enterprise HD, and Enterprise

Keep multiple Hazelcast IMDG clusters in sync on multi-site worldwide and cloud.

WAN Architecture Diagram

Imagine you have different data centers in New York, London and Tokyo each running an independent Hazelcast cluster. Every cluster would be operating at native speed in their own LAN (Local Area Network), but you also want some or all record sets in these clusters to be replicated to each other: updates in the Tokyo cluster should also replicate to London and New York and updates in the New York cluster are to be synchronized to the Tokyo and London clusters.

Hazelcast WAN Replication allows you to keep multiple Hazelcast clusters in sync by replicating their state over WAN environments such as the Internet. Hazelcast supports two different operation modes of WAN Replication:

  • Active-Passive: This mode is mostly used for failover scenarios where you want to replicate an active cluster to one or more passive clusters, for the purpose of maintaining a backup.
  • Active-Active: Every cluster is equal, each cluster replicates to all other clusters. This is normally used to connect different clients to different clusters for the sake of the shortest path between client and server.

The Value of the WAN Replication

  • A pluggable IMDG extension when you need to go multi-site with your distributed Hazelcast IMDG application:
    • Advanced configuration options and capabilities with the usual Hazelcast IMDG configuration style you already familiar with.
      Plays well with the Security Suite.
    • Management Center allows you to monitor your WAN Replication schemes, initiate a synchronization operation on your cache for a target cluster, and add a WAN replication configuration dynamically to your cluster.
  • Do not struggle with obvious and hidden pitfalls & challenges in distributed computing. Preserve your business continuity and speed both on multi-site and cloud. Hazelcast WAN Replication is a complete solution from the creators of the fastest distributed cache — stable at vertical and horizontal scale.
  • Hazelcast WAN Replication is cloud-ready: Use Hazelcast’s Discovery SPI to set-up your WAN replication with endpoints on various cloud infrastructures including Amazon EC2, Pivotal Cloud Foundry, OpenShift, and Azure where the IP address is not known in advance.
The value of WAN replication
Deployment Options Supported
On Premise Yes
Azure Yes
Google Cloud Platform No – Available with PCF or Openshift
Pivotal Cloud Foundry (PCF) Yes
OpenShift / Kubernetes Yes
Hybrid Yes

Main Features of Hazelcast WAN Replication

  • Multiple configurable features to cover typical scenarios:
    • Data Recovery (i.e. Active-Passive or One-way mode)
    • Geographic Locality (i.e. Active-Active or Two-way mode)
    • Test / development environment set-up
  • Both static and cloud endpoints are supported.
  • Supported data structures and merge policies
    • Hazelcast Map (IMap): PutIfAbsent, HigherHits, PassThrough, LatestUpdate
    • Hazelcast JCache (ICache): HigherHits, PassThrough
  • Monitoring and synchronization through Management Center.
  • On-demand synchronization for a specific target cluster:
    • Default Synchronization: Sends all the data to a target cluster to align the state of the target with the source one.
    • Delta Synchronization using Merkle Trees: Synchronize only the different entries instead of sending all entries.
  • Configurable replication batch size, batch maximum delay, and response timeout.
  • Configurable replication queue size for huge clusters or high data mutation rates.
  • Different behaviors when the replication queue becomes full: Discard after mutation, throw exception, throw exception only if replication active.
  • Interception of WAN replication events before they are placed to WAN event replication queues via the Event Filtering API.
  • Two acknowledgment (ACK) types depending on your consistency requirements.
    • ACK_ON_RECEIPT: Events that are received by target cluster that are considered as successful.
    • ACK_ON_OPERATION_COMPLETE: This option guarantees that the event is received by the target cluster and it is processed.
  • Generic WAN Replication Endpoints: Hazelcast Enterprise users can create their own WAN replication publishers and/or consumers and use them seamlessly instead of out of the box WAN replication implementations that come with Hazelcast Enterprise:
    • WanBatchReplication sends replication events to the target cluster after either a pre-defined number of replication events are generated or a pre-defined amount of time is passed.
    • SolaceWanPublisher allows WAN Replication users to use Solace, a high-performance enterprise-grade messaging solution, rather than direct cluster socket connections. The user could then make use of Solace’s guarantees for message delivery and also their monitoring tools.