Local and Shared Directories and Domains in Lion Server

By John Rizzo from Mac OS X Lion Server For Dummies

Lion Server can host a local directory for a small network. It can also host a shared directory as your user base increases. Its ability to do both makes Lion Server a very flexible platform.

Both client computers and servers store account data and information about the computer in a local database on each system. These databases of user information can’t be distributed among multiple computers. Even if you create a network directory, each computer will still have a local database with one or more user accounts in it.

Lion Server can store the network user accounts in its local directory. You know that they’re in the local directory because you see these users in System Preferences (as well as in the Server app).

A local directory may work for a small network of users with a single server and few network services. But if you had multiple servers, you’d have to set up accounts on every server machine on the network, and users would find themselves using different passwords for different file servers. You also can’t use Profile Manager if you don’t have a shared network directory.

With a shared directory, multiple servers share the account data, and users can log on to multiple file servers using the same account and password. Users that are bound, or connected, with a directory can access any of the services that reside on servers that are also bound to the same directory.

The use of shared directories goes much further, allowing administrators to manage clients and set password policies. It also enables servers to host home folders for computer users. A server-based home folder means that a user can log on to any computer on the network and have access to her data and settings.

Local and shared directories are also sometimes referred to as local and shared domains. In this context, a domain doesn’t refer to registered Internet domains but is used in the sense of spheres of influence. A local domain has an effect on only one computer. A shared domain covers a certain area of a network of computers.

Don’t get confused if you see directory domains that end in .com or .net, like Internet domains. The reason has to do with directory services’ heavy reliance on DNS (domain name server).