Configuring Bridge for WAN Replication

Remote data replication is a critical component for any plan to ensure effective and efficient protection of data and rapid recovery from a major interruption. Synchronous replication of data is good internally for the cluster but its impact on performance becomes a significant consideration when two clusters of cache are geographically separated. Bridge topology is designed for the scenarios, which involve replication of data from one on-site cache(s) to another on-site/off-site cache(s) across the WAN for disaster recovery. Due to asynchronous replication, all clients connected to the active cache(s) get an impression that the operations are being performed on the active cache while a complete backup is taken to the other cache(s) seamlessly.

When an operation is performed on the source cache, it is asynchronously handed over to the bridge cache. This operation is then queued in a queue maintained by the bridge cache. Operations from the queue are transferred to the target cache when bridge finds the target cache available and ready to accept operations. With the bridge topology, it is ensured that:

  • There is no performance degradation.
  • Operations are performed in same sequence as they were on original cache.
  • Operations are not lost in case of connection failure.

NCache provides the following Bridge topologies:

  • Active-Passive (one Active and one Passive Cache)
  • Active-Active (two Active Caches and no Passive Cache)

Active-Passive

This bridge topology has one active and one passive cache.

Three NCache Clusters participate in Active-Passive topology:

  1. An active cache (replicated, partitioned, mirrored or partitioned-replica), where all clients connect and perform read and write operations.

  2. A passive cache (replicated, partitioned, mirrored or partitioned-replica), where all operations performed on the active cache are replicated. Clients can connect to passive cache and perform both read and write operations but those operations are not replicated to the other cache. Modifications can be done at passive cache if required.

  3. A bridge cache between the active cache and the passive cache.

Active-Active

This bridge topology has two active caches but no passive cache.

Three NCache Clusters participate in the Active-Active topology:

  1. Two active caches (replicated, partitioned, mirrored or partitioned-replica), where all clients connect and perform read and write operations. Here any updates to the cache are applied asynchronously to the other cache.

  2. A bridge cache between both the active caches.

Note

This feature is only available in NCache Enterprise edition.

This section explains what is bridge, the operations that can be performed on a bridge and describes how to configure different bridge settings.

In This Section

Creating Clustered Bridge
Explains how to create a clustered bridge.

Adding Clustered Caches to Bridge
Explains how to add clustered caches to the bridge.

Configuring Bridge Settings
Describes what are basic bridge settings and how can they be configured.

Configuring Conflict Resolver
Explains how the conflict, if occurred in bridge operations, can be resolved.

Changing Cache Synchronization Modes
Explains how to change the synchronization mode of clustered cache connected to the bridge

Configuring Master Cache
Explains how an active cache (connected to a bridge) can be made a master cache.

Force State Transfer
Explains how to carry out state transfer explicitly between master cache and bridge.

Connect/Disconnect a Cache
Explains how to connect/disconnect a running cluster to bridge

Remove a Cache from Bridge
Explains how to remove a cache from bridge once it is stopped.

Bridge Management
Explains different bridge management operations and their usage.