Multiple instances that belong to the same or multiple trees can be used in the following scenarios effectively.
In large enterprises, you can provide load balancing and high availability of eDirectory services.
For example, if you have three replica servers running LDAP services on ports 1524, 2524, and 3524, respectively, you can configure a new instance of eDirectory and provide a high-availability LDAP service on a new port 636.
You can leverage high-end hardware across departments in an organization by configuring multiple instances on a single host.
Universities: Many enthusiasts (students) can evaluate eDirectory from the same host using the multiple instances.
Training for eDirectory administration:
Participants can try out administration using the multiple instances.
Instructors can use a single host to teach a class of students. Each student can have his own tree.