Distributing Your Data92 Red Hat Directory Server Deployment Guide • May 2005The database is the basic unit you use for jobs such as replication, performingbackups, and restoring data. You can carve a single directory into manageablechunks and assign them to separate databases. These databases can then bedistributed among a number of servers, reducing the workload for each server.You can store more than one database on a single server. For example, one servermight contain three different databases.When you divide your directory tree across several databases, each databasecontains a portion of your directory tree, called a suffix. For example, you can usea database to store the entries in the ou=people,dc=example,dc=com suffix, orbranch, of your directory tree.When you divide your directory among several servers, each server is responsiblefor only a part of the directory tree. The distributed directory works similarly tothe Domain Name Service (DNS), which assigns each portion of the DNSnamespace to a particular DNS server. Likewise, you can distribute yourdirectory namespace across servers while maintaining a directory that, from aclient’s point of view, appears to be a single directory tree.The Directory Server also provides knowledge references, mechanisms for linkingdirectory data stored in different databases. Directory Server includes two typesof knowledge references, referrals and chaining.The remainder of this chapter describes databases and knowledge references,explains the differences between the two types of knowledge references, anddescribes how you can design indexes to improve the performance of yourdatabases.Distributing Your DataDistributing your data allows you to scale your directory across multiple serverswithout physically containing those directory entries on each server in yourenterprise. A distributed directory can thus hold a much larger number of entriesthan would be possible with a single server.In addition, you can configure your directory to hide the distributing details fromthe user. As far as users and applications are concerned, there is simply a singledirectory that answers their directory queries.The following sections describe the mechanics of data distribution in more detail:• About Using Multiple Databases• About Suffixes
