Scalability of the common services tier

IBM® InfoSphere® Information Server is built on a highly scalable software architecture that delivers high levels of throughput and performance.

IBM InfoSphere Information Server services are hosted by IBM WebSphere® Application Server Network Deployment (ND), which is a J2EE-compliant application server. You can implement WebSphere Application Server cluster topologies to maximize the number of users who can use the system concurrently.

The term cluster used within a WebSphere Application Server context refers to a set of application servers that are managed together and participate in workload management.

The following WebSphere Application Server cluster topologies are supported:

  • Multiple application server instances within the same host computer (vertical clustering). Vertical clustering allows the system to maximize the resource allocation of cluster members, which improves performance.
  • Members of the same cluster on multiple host computers (horizontal clustering). Horizontal clustering allows the InfoSphere Information Server services tier to run on several nodes, but still operate with clients as a single system instance. This configuration makes the most effective use of hardware resources. Also, if a node becomes unavailable, its workload can be routed to other nodes in the cluster, which improves availability.

To implement a WebSphere Application Server clustering topology, you must also deploy a Web server or a load balancer as a front end to the cluster. A front-end Web server dispatches Web requests to cluster members according to preconfigured policies. A load balancer balances Web requests across cluster members. Either solution increases performance and security because the Web server or load balancer guarantees a unique HTTP entry point to the cluster.

You can implement an IP sprayer topology that consists of load balancers that are upstream of front-end Web servers. This topology allows intelligent load balancing among Web servers based on server availability and workload capacity.

To increase security, you can set up firewalls and create a DMZ to protect each tier within your WebSphere Application Server topology. To increase availability, you can also set up backup Web servers and load balancers.