Version Compatibility
Available in ActiveMQ 5.8.0 and newer

Version Compatibility

Available in ActiveMQ 5.8.0 and newer

LevelDB is a file based persistence database that is local to the message broker that is using it.
It has been optimized to provide even faster persistence than KahaDB. It's similar to KahahDB but
@@ -112,6 +113,11 @@ stalls.

For tuning locking properties please take a look at Pluggable storage lockers

+ +

Also See

+ +

Replicated LevelDB Store An extended version of this store which self replicates to other broker nodes to increase message availability.

Master Slave Type	Requirements	Pros	Cons
Shared File System Master Slave	A shared file system such as a SAN	Run as many slaves as required. Automatic recovery of old masters	Requires shared file system
JDBC Master Slave	A Shared database	Run as many slaves as required. Automatic recovery of old masters	Requires a shared database. Also relatively slow as it cannot use the high performance journal

Master Slave Type	Requirements	Pros	Cons
Shared File System Master Slave	A shared file system such as a SAN	Run as many slaves as required. Automatic recovery of old masters	Requires shared file system
JDBC Master Slave	A Shared database	Run as many slaves as required. Automatic recovery of old masters	Requires a shared database. Also relatively slow as it cannot use the high performance journal
Replicated LevelDB Store	ZooKeeper Server	Run as many slaves as required. Automatic recovery of old masters. Very fast.	Requires a ZooKeeper server.

If you are using a shared network file system such as a SAN we recommend a Shared File System Master Slave. If you are happy to dispense with the high performance journal and are using pure JDBC as your persistence engine then you should use JDBC Master Slave instead. For those willing to try out new tech, the Replicated LevelDB Store gives speeds similar to a SAN solution without the hassle of having to setup a highly available shared file system.

Pure Master Slave

This feature has been deprecated and will be removed in version 5.8
This feature will be removed in 5.8 as it has not evolved to be production ready. You are advised to use shared storage master/slave. see AMQ-4165

This feature has been deprecated and will be removed in version 5.8
This feature will be removed in 5.8 as it has not evolved to be production ready.
+You are advised to use shared storage master/slave or the Replicated LevelDB Store.
+See AMQ-4165

A Pure Master Slave configuration provides a basic shared nothing, fully replicated topology which does not depend on a shared file system or shared database.

Modified: websites/production/activemq/content/replicated-leveldb-store.html ============================================================================== --- websites/production/activemq/content/replicated-leveldb-store.html (original) +++ websites/production/activemq/content/replicated-leveldb-store.html Wed May 8 00:22:52 2013 @@ -99,6 +99,21 @@ node with the lastest updates. The node it's recommend that you run with at least 3 replica nodes so that you can take one down without suffering
a service outage.

Deployment Tips

+ +

Clients should be using the Failover Transport to connect to the broker
+nodes in the replication cluster. e.g. using a URL something like the following:

+ +

+failover:(tcp://broker1:61616,tcp://broker2:61616,tcp://broker3:61616)
+

+ +

You should run at least 3 ZooKeeper server nodes so that the ZooKeeper service is highly available.
+Don't overcommit your ZooKeeper servers. An overworked ZooKeeper might start thinking live
+replication nodes have gone online due to delays in processing their 'keep-alive' messages.

Configuration

You can configure ActiveMQ to use LevelDB for its persistence adapter - like below :

Modified: websites/production/activemq/content/shared-file-system-master-slave.html ============================================================================== --- websites/production/activemq/content/shared-file-system-master-slave.html (original) +++ websites/production/activemq/content/shared-file-system-master-slave.html Wed May 8 00:22:52 2013 @@ -103,6 +103,14 @@ GFS: fully supports Cluster-wide flocks

     <persistenceAdapter>
+      <levelDB directory="/sharedFileSystem/sharedBrokerData"/>
+    </persistenceAdapter>
+

or:

+    <persistenceAdapter>
       <amqPersistenceAdapter directory="/sharedFileSystem/sharedBrokerData"/>
     </persistenceAdapter>