Changes to the File Replication Service

This article describes changes to the File Replication Service (FRS) in a Windows 2000 Post-Service Pack 2 (SP2) hotfix that improve the robustness of the service. These changes address behavior that may cause FRS to stop replicating. The changes also include manageability improvements and minor problem fixes. A supported feature that modifies the default behavior of the product is available from Microsoft. However, this feature is intended to modify only the behavior that this article describes. Apply this feature only to systems that specifically require it.

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Due to directory access changes in this release, the replication of files and directories will fail with an "access denied" error if the System account does not have full control of all folders in the directory tree that is replicated by the File Replication Service (FRS). For additional information, click the article number below to view the article in the Microsoft Knowledge Base:

This section describes these changes.

FRS Detects and Suppresses Excessive Replication

Whenever data is written to a file, that file is staged for replication. However, there are some cases where data is written that do not change the file at all. For example, if you use Group Policy to apply file permissions, the file is not changed. If you use Group Policy to enforce permissions on files in SYSVOL, that policy is applied every five minutes by default. As a result, FRS attempts to replicate the "changed" files even though the permissions were not necessarily modified.

In the post-SP2 hotfix, FRS replicates a file if no actual changes were made to it. In addition, if FRS detects a significant increase in the number of changes made to a file, it logs an event ID 13567 message in the FRS event log.

FRS Performs Serialized Version Vector Joins

When a member first joins a replica set, FRS locates the upstream partners and requests a list of all the files in the replica set. In versions of Windows 2000 before this post-SP2 hotfix, FRS obtains this list of files from all upstream partners at the same time, which results in a duplication of effort on those partners. In the Windows 2000 post-SP2 hotfix, this behavior has been changed so that FRS obtains the list from the upstream partners one after the other. As a result, if the first upstream partner is synchronized, the new member replicates all the files from it. The version vector join process with each subsequent partner is much shorter because the new member does not need to replicate any files. If the initial partner is not synchronized, subsequent joins result in updates that are sent to the new member.

FRS Does Not Stop Replicating If the Staging Area Is Filled

When FRS tries to allocate space for a staging file and is not successful because either there is not enough space or because the amount of space in use has reached 90 percent of the staging space limit parameter (the default value is 660 megabytes [MB]), FRS starts to delete staging files. Staged files are deleted (in the order of the longest time since the last access) until the amount of space in use has dropped below 60 percent of the staging space limit parameter. As a result, FRS no longer stops replicating if the staging area runs out of free space. This means that if a replica set member goes offline for an extended period of time, it does not block replication on an upstream member because the staging area is filled.

For additional information about the staging space limit parameter, click the article number below to view the article in the Microsoft Knowledge Base:

Increase in NTFS Journal Size

FRS uses the NTFS file system journal to alert it when changes are made to a file. If the journal wraps, FRS loses track of the changes it needed to replicate, and you must perform a non-authoritative restore operation. The NTFS journal size has been increased to 128 MB to reduce the possibility of a journal wrap.

Changes to the Automatic Non-Authoritative Restore Functionality

FRS no longer performs an automatic non-authoritative restore if a journal wrap condition is detected. Instead, it logs an event ID 13568 message to the FRS event log to remind you to perform the operation at a convenient time. A registry key has been provided to configure an automatic non-authoritative restore operation if you want to use that functionality. However, when you configure this setting, the contents of the replica tree may be made unavailable while the restore operation is taking place.

Time Out Problems

The following time out problems have been addressed:

• The time out problem that occurs when a large number of members attempt to synchronize all at once with an upstream partner.
• The time out problem that occurs when a stage file for a very large file is being created.

Changes to the Way You Change the FRS Staging Path

You can now change the FRS staging path without having to perform a non-authoritative restore operation. When FRS detects a change to the staging path, it logs an event ID 13563 message in the FRS event log that describes the procedure. The following section contains the text for this message:

Other Changes

• Event messages that are logged when a domain controller is unable to create the Sysvol share are now more descriptive.
• The FRS update for Windows 2000 Service Pack 2 (SP2) enabled compression on the wire. If the replicated data is already compressed, the resulting file may actually be larger than the original, and the FRS silently does not replicate. This problem has been resolved.
• Changes to a Microsoft Excel spreadsheet on one replica may cause the same file to be deleted on all downstream partners. This problem has been fixed.
• The FRS service must build a table that links volume serial numbers to drive letters. This table is used to make sure that the service can find the correct volume for the replicated directories even if drive letter assignments change. FRS will no longer poll removable drives when it builds this table.
• Event messages that include instructions on how to update the registry have been corrected.
• A memory leak that can be significant in environments with a large number of domain controllers has been fixed.

For additional information, click the article number below to view the article in the Microsoft Knowledge Base: For additional information about how to obtain a hotfix for Windows 2000 Datacenter Server, click the article number below to view the article in the Microsoft Knowledge Base: