Traditional Multi-Instances architecture

Multitenancy Defined

(From Wikipedia)

Multitenancy refers to a principle in software architecture where a single instance of the software runs on a server, serving multiple client organizations (tenants). Multitenancy is contrasted with a multi-instance architecture where separate software instances (or hardware systems) are set up for different client organizations. With a multitenant architecture, a software application is designed to virtually partition its data and configuration, and each client organization works with a customized virtual application instance.

Multitenancy is also regarded as one of the essential attributes of cloud computing.[1]

Before Fortress

Client data had to be maintained on separate instances of LDAP server.