i2 Analyze with high availability

i2 Analyze supports an active/active high availability and disaster recovery deployment pattern. The only component that is not deployed in an active/active state is the database management system, which uses an active/passive pattern where one instance of the Information Store database is the primary and others are standby.

The following diagram shows the minimum number of servers for a deployment with fault tolerance for one server failure of each component:

After you read the following information that explains how each component is used in a deployment with high availability, follow the instructions to deploy i2 Analyze in this pattern. For more information about how to deploy i2 Analyze, see Deploying i2 Analyze with high availability.

Load balancer

A load balancer is required to route requests from clients to the Liberty servers that host the i2 Analyze application. Additionally, the load balancer is used to monitor the status of the Liberty servers in a deployment. The load balancer must route requests only to servers that report their status as "live".

After you deploy i2 Analyze with a load balancer, you can make requests to i2 Analyze through the load balancer only.

You can also use the load balancer to distribute requests from clients across the servers in your deployment. The load balancer must provide server persistence for users.

To provide high availability of Liberty, and the i2 Analyze application, you can deploy i2 Analyze on multiple Liberty servers. Each Liberty server can process requests from clients to connect to i2 Analyze.

In a deployment with multiple Liberty servers, one is elected the leader. The leader can process requests that require exclusive access to the database. The actions that are required to be completed on the leader Liberty are described in Liberty leadership configuration.

At a minimum, two Liberty servers are required.
Database management system
To provide high availability of the Information Store database, use the functions provided by your database management system to replicate the primary database to at least one standby instance. i2 Analyze connects to the primary instance at one time, with the contents of the Information Store database replicated to the standby instances.

If the primary instance fails, one of the standby instances becomes the primary. When a standby becomes the primary, it must be configured to be read and writable. This means that i2 Analyze can continue to function when the initial primary server fails.

For Db2, at a minimum one primary server and one standby server is required.

For SQL Server, at a minimum one primary server and two standby servers are required. If you are using basic availability groups, this is one standby server and one failover quorum witness.

i2 Analyze uses SolrCloud to deploy Solr with fault tolerance and high availability capabilities. To provide fault tolerance and high availability of the Solr cluster, deploy the cluster across at least two Solr nodes with each node on a separate server.

At a minimum, two Solr servers are required.

For more information about SolrCloud, see How SolrCloud Works.

To deploy ZooKeeper for high availability, deploy multiple ZooKeeper servers in a cluster known as an ensemble. For a highly available solution, Apache ZooKeeper recommend that you use an odd number of ZooKeeper servers in your ensemble. The ZooKeeper ensemble continues to function while there are more than 50% of the members online. This means, that if you have three ZooKeeper servers, you can continue operations when a single ZooKeeper server fails.

At a minimum, three ZooKeeper servers are required.

For more information about a multiple server ZooKeeper setup, see Clustered (Multi-Server) Setup.