Adding a New Member to an Existing Replica Set

  • Article

Applies To: Windows Server 2003, Windows Server 2003 R2, Windows Server 2003 with SP1, Windows Server 2003 with SP2

Before you add a new member to an existing replica set, determine how to source the new member. You have two choices:

  • Replicate the files to the new member across the network. When you replicate files across the network to the new member, you add the server as a link target within an existing replica set. When you add the new member to the topology, you can create a single inbound connection so that you source from a specific server, such as a server with fast connectivity, or you can add a computer with redundant inbound connections where it sources according to connection priority and schedule.

  • Prestage the files on the new member. When you prestage files, you use a backup program to back up the replica tree and restore it on the new member. Using a backup program is required to preserve the file object IDs and security descriptors. (Command-line tools such as Copy.exe, Xcopy.exe, and Robocopy.exe do not preserve these items, and they cannot be used to prestage files.) After you restore the files, FRS replicates to the new member any files that changed since the backup was created, thus minimizing the number of files that are replicated across the network.

The method you choose typically depends on the size of the replica set and the available network bandwidth. You should replicate files over the network only if one of the following conditions exists:

  • You have a high-bandwidth network, and you can afford to use part of that bandwidth for the initial replication.

  • You have a low-bandwidth network, and you can afford to use that bandwidth for initial replication, and you also have the time to wait for the initial replication to complete.

If neither of these conditions exists, you should prestage the new member.

The following sections describe three possible scenarios for adding a new replica member:

  • Prestaging a new replica member to avoid replicating files across the network.

  • Adding a new replica member that contains no content. In this scenario, files are replicated across the network.

  • Adding a new replica member that contains a copy of the content. In this scenario, the new member has an existing copy of the files, but these files are not prestaged. The files from the initial master are replicated across the network.

Prestaging a New Replica Member

In this scenario, you have an existing replica set, and you want to add a new replica member by prestaging it. After you prestage the new member and enable replication, FRS moves the prestaged files in the replica tree on the new member to the NtFrs_PreExisting____See_EventLog folder, but FRS then moves back to the replica tree any files that have the same object ID and content as the files in the master replica set. FRS replicates across the network only the files that were added or changed since you prestaged the files.

Before you can prestage a new replica member, one of the following events must occur:

  • At least seven days have passed since you enabled replication between the first two members.

  • You clear the outbound change log by modifying the registry on all direct upstream partners.

To prestage a new replica member, perform the following tasks:

  1. Configure the USN journal.

  2. Prestage the new replica member.

  3. Create a new link target, add it to the replica set, and then specify the staging directory location.

  4. Disable referrals to the new link target.

  5. Configure connection objects, the initial schedule, and connection priorities (custom topologies only).

  6. Adjust the size of the staging directory.

  7. Verify that replication is working on the new member.

  8. Enable referrals to the link target.

  9. Optimize the replication schedule.

  10. Configure connection priorities (standard topologies only).

For a Word document to assist you in completing each of these tasks, see "Prestaging a New Replica Member" (Sdcfsv_5.doc) on the Windows Server 2003 Deployment Kit companion CD (or see "Pre-staging a New Replica Member" on the Web at https://www.microsoft.com/reskit). After you complete these tasks, you can notify users that the DFS namespace is available.

Adding a New Replica Member That Contains No Content

In this scenario, the new replica member does not contain a copy of the replica tree. Data will replicate across the network according to the replication schedule.

To add a new replica member that contains no content, perform the following tasks:

  1. Configure the USN journal.

  2. Create a new link target, add it to the replica set, and then specify the staging directory location.

  3. Disable referrals to the new link target.

  4. Configure connection objects, the initial schedule, and connection priorities (custom topologies only).

  5. Adjust the size of the staging directory.

  6. Verify that replication is working on the new member.

  7. Enable referrals to the link target.

  8. Optimize the replication schedule (optional).

  9. Configure connection priorities (standard topologies only).

For a Word document to assist you in completing each of these tasks, see "Adding a New Replica Member that Contains No Content" (Sdcfsv_6.doc) on the Windows Server 2003 Deployment Kit companion CD (or see "Adding a New Replica Member that Contains No Content" on the Web at https://www.microsoft.com/reskit). After you complete these tasks, you can notify users that the DFS namespace is available.

Adding a New Replica Member That Contains a Copy of the Content

In this scenario, the new replica member already contains a copy of the replica tree. You might have copied the data to the server manually (using Robocopy, for example), but you have not prestaged the new member. (Remember that prestaging preserves the file object IDs and security descriptors.) Because the data is not prestaged, the initial master replicates the entire replica tree to the new member, even if the new member already contains identical files. On the new replica member, FRS moves any files that existed in the replica tree to a folder named "NtFrs_PreExisting____See_EventLog." After replication completes, you can either delete this folder or move any unique files back into the replica tree.

To add a new replica member that contains a copy of the content, perform the following tasks:

  1. Follow the procedures in "Adding a New Replica Member that Contains No Content" (Sdcfsv_6.doc) on the Windows Server 2003 Deployment Kit companion CD (or see "Adding a New Replica Member that Contains No Content" on the Web at https://www.microsoft.com/reskit).

  2. After replication completes, locate the folder "NtFrs_PreExisting____See_EventLog" on the new replica member.

  3. Do one of the following:

    • If the folder contains unique files that are not part of the replica set, copy those files back into the replica tree.

    • If you do not want to save any of the files, delete the folder.