The Windows 2000 version of Dfs allows child replica sets to be created in which a single Dfs leaf points to multiple shares on different servers the File Replication Service will keep the contents of all shares in sync with each other. This allows fault tolerance AND load balancing.

Members of a node replica set must:

1. All be members of the domain
2. Use NTFS 5.0
3. Must be on different servers. You cannot replicate between shares on the same server.

To add a new Dfs child replica member perform the following:

1. Ensure an up-to-date copy of the resource to which a new replica member is to be added is placed in the new share which will join the set
2. Start the Distributed File System MMC snap-in (Start - Programs - Administrative Tools - Distributed File System)
3. Right click on the child node you wish to add a replica to and select 'New Replica'
4. You will need to enter the UNC of the new share and you have the option for
   - Manual replication
   - Automatic replication
   'Manual replication' is useful if the contents are read-only documents which do not often change. Joint replication will replicate the contents of the shares with all members in the replica set. Click OK
5. The replication set topology dialog will be shown. Check replication has been enabled and click OK
   

Multi-master replication is used except on the first replication path where the contents of the Primary server is copied to the other members. Any content currently in the other shares is moved to a NtFrs-PreExisting subdirectory (but a checksum is performed and if the files match with the primary servers share they are moved back into the main directory to save network bandwidth in copying them from the Primary server).

Replication is every 15 minutes by default.

How do I create a Dfs root volume in Windows 2000?

Windows 2000 currently supports one Dfs root per server however this will be expanded in future versions of the operating system/service packs.

The Distributed File System has its own DFS Microsoft Management Console snap-in which has a shortcut on the Administrative Tools folder.

To create a new Dfs root perform the following:

1. Start the Distributed File System MMC snap-in (Start - Programs - Administrative Tools - Distributed File System)
2. Right click on the Distributed File System root and select 'New Dfs Root.'
   
3. The Dfs root creation wizard will be started, click Next to the introduction screen

4. The next screen gives the option of a fault-tolerant Dfs root which uses the Active Directory to store the information or a standalone Dfs root if the Active Directory is not available or not wanted. Select 'Create a domain Dfs root' and click Next
   Select a domain to use. A list of available domains will be displayed and the current domain will be selected as the current choice. Click Next. This screen is not displayed if you are not creating a fault-tolerant Dfs root.
5. You will need to select a server to host the Dfs root (a domain member if fault tolerant) and must be running the Dfs service. The current server will be selected but can be changed by typing a domain name or click Browse. Click Next
6. The next stage is to select a share to act as the Dfs root. A list of existing shares will be displayed or you can select to create a new share by entering a share name and location. Click Next
   
7. Each Dfs root requires a unique name and will, by default, be the name of the share although you can change this. You can also select to add the new Dfs root to the current console. Click Next
8. A summary screen will be displayed showing the domain, server, share and Dfs root name. Click Finish to create the Dfs root
9. Once complete a success message will be displayed. Click OK

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