Specifications

Lotus Redbooks Wiki – IBM Lotus Notes and Domino V8.5 Deployment Guide
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iNotes High Availability Configuration
Lotus iNotes is an enterprise application, and as an enterprise application requires scalability, high
availability and predictability. It can be integrated with a load balancer solution for distributing incoming
client requests across a group of servers to achieve this goals with transparency to users and Lotus iNotes
applications. When used with Lotus iNotes servers, a load balancer can help maximize the potential of Lotus
Domino server by providing a powerful, flexible, and scalable solution to peak-demand problems. The main
purpose of load balancing is to create a virtualized Lotus Domino iNotes server from a group of physical
servers or partitioned Lotus Domino servers.
Term explanation:
Scalability is the capability to dynamically or easily increase server capacity with additional number of
server or power of server to provide support of high load requests without impacting existing performance
and transparent to users.
High Availability (Failover) is the capability to remain available and accessible even during the failure of
one or more system in the group. When one of the servers fails, client requests will be continually serviced
by the other server with transparent to users. This eliminates any server as a single point of failure and
makes the site highly available.
Predictability (Balance) is the capability to have control to distribute load equally across the group of server
without overloading any server with transparent to users.
Lotus Domino Internet Cluster Manager for Lotus iNotes
Internet Cluster Manager (ICM) was introduced in Domino R5 enterprise release to serve as a liaison
between the HTTP clients and the HTTP servers of a Domino cluster. The HTTP clients direct requests for a
database to the ICM. The ICM maintains information on the availability of the Domino servers in the Domino
cluster, and also maintains information about the distribution of databases on the servers. The ICM
determines the best server to receive a particular client request and redirects the request to that server.
Two main reasons to use ICM:
1. Your organization might want to provide high availability to its customers using browsers to access
Domino Web applications. Therefore, you would install the ICM to provide failover support for your Lotus
iNotes servers.
2. Your organization might also want to provide scalability for its Domino Web applications. Therefore, you
would install the ICM and utilize load balancing of browser clients accessing your Lotus iNotes applications.
Load Balancer
A Load balancer or IP sprayer can be software based, for example Websphere Edge server, or a hardware
load balancing solution, like a Cisco content redirector, F5 Big-IP. It acts as proxy server and distributes
network or application traffic across a group of servers to increase capacity and reliability of applications. For
users, they only can see the load balancer virtual service and actual Lotus iNotes servers are hidden behind.
They improve the overall performance of applications by decreasing the burden on servers associated with
managing and maintaining application and network sessions, as well as by performing application-specific
tasks.