A major advantage of SIMS over competitors is its superior scalability, which enables populating large number of users on just one server. Although this provides excellent price versus performance advantages, it results in a single point of failure, where one failing machine could interrupt e-mail access for an entire user community.

To ensure reliability, SIMS 3.5 enables you to install on a Sun Enterprise Cluster by using the Sun Cluster 2.1 software. This capability provides automatic fail-over when a failure occurs.

See http://www.sun.com/clusters for information on Sun Cluster.

Topics in this chapter include:

		Other HA References in this Chapter
		SIMS Asymmetric HA Configuration
		Fail-over Procedure
		Directory Services Considerations