Locations define a group of servers with similar response time characteristics. Each location consists of a name and an ordered list of preferred failover locations. The Directory Proxy Server and each of the backend LDAP external servers can be assigned locations. These locations can be taken into account when deciding how to route requests, so that the server prefers to forward requests to Directory Server in the same data center over those in remote locations. As a rule of thumb, if you have multiple data centers then you should have a separate location for each one. In most environments, all Directory Proxy Server instances should have the same configuration except for the attribute that specifies the location of the Directory Proxy Server itself.
For example, a deployment consists of three data centers, one in New York, another in Chicago, and another in Los Angeles. In the New York data center, applications which reside in this data center prefer communicating with directories in this data center. If none of the servers are available, it prefers to failover to the data center in Chicago rather than the data center in Los Angeles. So the New York location contains an ordered list in which the Chicago location is preferred over the Los Angeles data center for failover.
For information about configuring locations, see Configuring Locations.