Introduction to FRS

File Replication service is a multithreaded replication engine that replaces the LMRepl service that is used in Microsoft® Windows NT®. Multithreaded means that several processes can run at the same time to handle multiple tasks. This allows FRS to replicate different files between different computers simultaneously.

FRS does not guarantee the order in which files arrive. Files begin replication in sequential order based on when the files are closed, but file size and link speed determine the order of completion. Because FRS replicates only whole files, the entire file is replicated even if you change only a single byte in the file.

FRS expands on the functionality provided by LMRepl with the following enhancements:

  • Multimaster replication of files and folders for allowing updates to occur independently on any server in the domain.

  • Site-aware clients (Microsoft® Windows® 2000, Microsoft® Windows NT® version 4.0, Microsoft® Windows® 95, and Microsoft® Windows 98 with the Active Directory add-on) for locating nearby servers hosting SYSVOL and Dfs content.

  • Configurable schedules for replicating Dfs and SYSVOL content between sites.

  • Automatic replication of folder and file attributes including ACLs.

Like LMRepl, FRS is automatically installed on Windows 2000 domain controllers and configured to start automatically. For member servers, the service start value is initially set to manual.


There is no administrative console for FRS. SYSVOL replication occurs automatically just like directory replication. Replication of Dfs files and folders is controlled by the Dfs administrative snap-in.

Although Active Directory replication and File Replication service are separate mechanisms, they are conceptually similar. Therefore, it can be useful to read about directory replication when you are learning about FRS. For information about directory replication, see "Active Directory Replication" in this book.

Key Terms
FRS terms that you need to know before reading further are:
Replication . The process of copying data, from one computer to another, that converges to an identical data set over time. Replication enhances availability and file sharing by duplicating shared files.
Replica . A member of a replica set that contains a copy of a shared folder or file.
Replica set. Two or more copies of a shared folder that participate in replication. Each copy must be located on a different computer.
Initial master . First member in a replica set that is the starting point for automatic replication. This means the files and folders in that replica are replicated to other replicas for the first replication cycle. —