Replication Overview in the Windows NT Operating System (101473)

SUMMARY

Windows NT supports replication to maintain specific, identical sets of files and directories on different computers. Changes to information on one computer is automatically replicated to other computers configured to receive those changes. One common use for replication maintains identical login scripts for all servers that process login requests in a domain. It can also be used to replicate changes to other files, such as database files that are updated regularly and must be duplicated exactly on other servers to maintain a copy of the database.

MORE INFORMATION

To support replication, Windows NT requires an export server and an import server. The export server must maintain the master copy of the files and directories to replicate in an export directory (by default, C:\WINNT\SYSTEM32\REPL\EXPORT). An export server can replicate directory trees that contain as many as 32 subdirectories. After configuring a server to replicate files, the EXPORT directory on the export server is automatically shared as follows:

Repl$ as a hidden administrative share that allows the Administrators local group access with Full Control permission and the Replicator local group account access with Read permission.

Import servers can be computers with Windows NT Advanced Server, Windows NT, or OS/2 LAN Manager 2.x servers. Import servers receive the master copy of the files and directories from the export directory on the export server and place them into an import directory (by default, C:\WINNT\SYSTEM32\REPL\IMPORT). After configuring the system for replication, the IMPORT directory on each import server is automatically shared as the IMPORT share that allows the Everyone account access with Full Control permissions.

Replication goes from the export server to the import server(s), not the other direction, unless an Advanced Server has been configured as both an export and an import server. (A Windows NT workstation cannot be configured as an export server.) At regular intervals, the import server establishes a session by logging onto the export server. If the export server contains files or directories that have been modified since the last update, these files are replicated to the import server. If any files or directories have been deleted from the import server or if new files have been created on the export server, the export server replicates the files and directories not present and resynchronizes the import directory.

Replication can occur between specific computers or between domains. If you activate replication on the import server without specifying the name of a computer or of a domain, the import server automatically replicates files from the export server in its domain. An export server can also export files to a specified domain. Any computer configured for import replication in the domain receives any changes to files and directories. You can also configure replication to occur between machines if a trust relationship exists between their domains.

Additional Information:

See article 104204 in the Microsoft Knowledge Base for more information.