Subfolder file content on an upstream member does not match subfolder file content on downstream members in a DFSR configuration in Windows Server 2003 R2

You create a Distributed File System Replication (DFSR) configuration in Windows Server 2003 R2. On some replication group members, you use the File Server Resource Management (FSRM) tool to create the same hard quota on a subfolder under the replicated folder. After you write to a subfolder on an upstream member, the file content in the subfolder on the upstream member may not match the file content in the subfolder on other downstream members. Additionally, the replication process may be slow, and the DFSR backlog increases.

When this problem occurs, event ID 4502 is logged in the DFS Replication event log on the downstream members. This event resembles the following:

Type: Warning
Event Source: DFSR
Category: None
Event ID: 4502
Description:

The DFS Replication service encountered errors replicating one or more files because adequate free space was not available on volume C:. This volume contains the replicated folder, the staging folder, or both. Please make sure that enough free space is available on this volume for replication to proceed. The service will retry replication periodically.

Additional Information:
Staging Folder: C:\FSRM_Repro\DfsrPrivate\Staging\ContentSet{F6817A43-B01B-45CD-AB0A-D5FEAAF62E7B}-{ACBFFFBB-B746-453C-8B85-CA0EF7244107}
Replicated Folder Root: C:\FSRM_Repro
ReplicatedFolder Name: FSRM_Repro
Replicated Folder ID: F6817A43-B01B-45CD-AB0A-D5FEAAF62E7B
Replication Group Name: FSRM_RG
Replication Group ID: 8D3BE270-BE2C-4573-A193-37EF45F49EDD
Member ID: ACBFFFBB-B746-453C-8B85-CA0EF7244107
Volume: 3E766AD0-9BF5-11D9-BB89-806E6F6E6963

When you write to a subfolder on the upstream member, FSRM allows for 40 kilobytes (KB) to 70 KB more data than the hard quota limit for data that is written to the subfolder. However, the hard quota limit on the downstream member stops the replication if the hard quota limit is exceeded on the upstream member. On downstream members, DFSR cannot move files from the Replicated_Folder\DFSRPrivate\Installing folder into the subfolder.

Additionally, DFSR has an automatic recover mechanism. When DFSR detects event ID 4502, DFSR starts to perform the staging cleanup operation in the Replicated_Folder\DfsrPrivate\Staging folder to free disk space. During the staging cleanup operation, DFSR stops other replication threads on the volume. However, the problem is not related to the disk space. Instead, the problem is related to the subfolder that has the hard quota set. Therefore, the cleanup operation does not resolve the problem. The next time DFSR tries to move files from the Replicated_Folder\DFSRPrivate\Installing folder to the subfolder, the problem persists. This causes DFSR to perform the staging cleanup operation again. Therefore, replication performance is severely affected.

How to determine the quota usage for a folder

On the upstream member, you can run the following command at a command prompt to determine the quota usage on the subfolder.If the hard quota limit is exceeded, the command returns results that resemble the following.The sample result shows that the hard quota limit on the upstream member is exceeded by 70 KB. In this case, the replication is blocked on the downstream member. Therefore, the subfolder on the upstream member does not match the folder on the downstream members.

A supported hotfix is now available from Microsoft. However, it is intended to correct only the problem that is described in this article. Apply it only to systems that are experiencing this specific problem. This hotfix may receive additional testing. Therefore, if you are not severely affected by this problem, we recommend that you wait for the next software update that contains this hotfix.

To resolve this problem immediately, contact Microsoft Customer Support Services to obtain the hotfix. For a complete list of Microsoft Customer Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question.

Prerequisites

To apply this hotfix, you must be running Windows Server 2003 R2 or Windows Server 2003 R2 Service Pack 2 on the computer.

Restart requirement

You must restart the computer after you apply this hotfix.

Hotfix replacement information

This hotfix does not replace any other hotfixes.

How to enable this hotfix

Important This section, method, or task contains steps that tell you how to modify the registry. However, serious problems might occur if you modify the registry incorrectly. Therefore, make sure that you follow these steps carefully. For added protection, back up the registry before you modify it. Then, you can restore the registry if a problem occurs. For more information about how to back up and restore the registry, click the following article number to view the article in the Microsoft Knowledge Base: Note You must install and enable this hotfix on all members that have the hard quota set on the subfolder.

To enable this hotfix, follow these steps:

1. Click Start, click Run, type regedit, and then click OK.
2. Locate the following registry subkey:
   HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Quota
3. Create the following registry entries under the Quota registry key:

   Registry entry	Type	Value	Description
   BypassQuota	DWORD Value	1	Setting this registry entry to 1 enables the quota bypass feature
   BypassQuotaQuantityInKB	DWORD Value	2048 (Decimal)	If a thread's access token has the admin privilege and the restore privilege, the thread can bypass the quota by the value that you specify in kilobytes. 2048 is the recommended value. Note The DFS Replication service has the admin privilege and the restore privilege.

4. Restart the computer.

File information

The English version of this hotfix has the file attributes (or later file attributes) that are listed in the following table. The dates and times for these files are listed in Coordinated Universal Time (UTC). When you view the file information, it is converted to local time. To find the difference between UTC and local time, use the Time Zone tab in the Date and Time item in Control Panel.

Windows Server 2003 R2, x86-based versions

Windows Server 2003 R2, x64-based versions

Windows Server 2003 R2 with Service Pack 2, x86-based versions

Windows Server 2003 R2 with Service Pack 2, x64-based versions

To work around this problem, use a soft quota limit instead of a hard quota limit on the subfolder.

Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.

In a DFSR configuration in which you set a hard quota on members of the replication group, we highly recommend that you write to the subfolder only on one member of the replication group. If you write to the subfolder on different members of the replication group, you are likely to exceed the hard quota limit. This causes the replication to fail. You should consider this issue when you are planning the DFS Namespace setup and failover strategy. This hotfix enables DFSR to work together with FSRM hard quota limits when changes to the subfolder are made on only one member. This behavior matches a pure DFSR backup scenario. In the pure DFSR backup scenario, changes are made on the branch server instead of on the hub backup servers.

When you use quota software, we recommend that you also install the DFSR hotfix that is described in Microsoft Knowledge Base article 958876. For more information, click the following article number to view the article in the Microsoft Knowledge Base:
For more information about software update terminology, click the following article number to view the article in the Microsoft Knowledge Base: