Introduction:
Backups of Distributed File System Replication (DFSR) data on Windows 2003 R2 or Windows 2008 using NetBackup 6.5 GA - 6.5.3.1 complete with a NetBackup Status Code 0, but the data is not backed up.

NetBackup 6.5 introduced support for the DFSR feature (namely DFS Namespaces and DFS Replication).  With the introduction of DFSR, a writer was made available which allows the backup to occur during shadow copy backup. By design, the DFSR writer excludes the DFS namespaces and the shared folders from a normal file system backup.  

NOTE: While support for Windows 2003 R2 was introduced at NetBackup 5.0 MP6 and 5.1 MP4, support for the DFSR feature was not implemented until NetBackup 6.5.  If the DFSR feature is used on systems running versions of NetBackup prior to 6.5, additional steps are necessary to protect the replicated data.  Please review the workaround section for the necessary information.  

The bpbkar log file on the affected client shows the following error:

8:01:21.486 PM: [5716.6124] <4> tar_backup_vxbsa::add: INF - Volume snapshots not enabled for: ?w

it then shows the following messages:

8:01:28.455 PM: [5716.6124] <2> ov_log::V_GlobalLog: ERR - Unknown Shadow Copy DBLK SubType (36)
8:01:28.455 PM: [5716.6124] <4> dos_backup::tfs_findfirst: WRN - unable to find first file: 'Shadow Copy Components:\User Data\Distributed File System Replication\DfsrReplicatedFolders\CHIC-Home\'

What is Affected:
In order to be affected by this issue, all of the following criteria must be met:

- The server must be using NetBackup 6.5 GA, 6.5.1, 6.5.2, 6.5.2a, 6.5.3 or 6.5.3.1

- The server must be running Windows 2003 R2 (or Windows 2008 where supported).

- The server must be using the DSFR feature.

Note: If DSFR is enabled with a version of NetBackup that does not support DSFR, Symantec strongly recommends implementing the Workaround, listed below, for NetBackup versions prior to 6.5.

How to Determine if Affected:
To determine the version of NetBackup, open the NetBackup Administrative Console, and from the Help menu, select "About NetBackup", and review the resulting screen.  If the version shown in NetBackup 6.5 GA, 6.5.1, 6.5.2, 6.5.2a or 6.5.3, the machine may be affected.  

Figure 1: NetBackup version
 

To determine the version of Microsoft running on the server, click on Start, Run, and enter "winver" without the quotation marks.  Review the resulting dialog to determine the version of Windows in use.  

Figure 2: Windows version
 

To determine if Microsoft DFSR is in use, go to Start, Settings, Control Panel, Administrative Tools, and then open Services.  If the "DFSR Service" is present and running, the machine is affected.  

Figure 3: DSFR Service
 

Formal Resolution:
Symantec Corporation has acknowledged that the above-mentioned issue is present in the current version(s) of the product(s) mentioned at the end of this article. Symantec Corporation is committed to product quality and satisfied customers.  

The fix for this issue is currently scheduled to be included in NetBackup Enterprise Server 6.5.4.  Please note that Symantec Corporation reserves the right to remove any fix from the targeted release if it does not pass quality assurance tests or introduces new risks to overall code stability.  Symantec's plans are subject to change and any action taken by you based on the above information or your reliance upon the above information is made at your own risk.  Please refer to the Release Update readme or contact NetBackup Enterprise Support to confirm this issue (ET1218121) was included in the update.  

It is recommended to upgrade to NetBackup 6.5.3 if experiencing this issue, as well as performing any needed workarounds listed in this document.  Changes have been made in 6.5.3 to help prevent reporting a Status 0 if the above conditions occur and report a Status 1 (partially successful) instead.  6.5.3 is available for download in the related documents section below, as well as through the following link:
 http://www.symantec.com/enterprise/support/downloads.jsp?pid=15143

However it is still recommended to upgrade to 6.5.4 when its released if the conditions in this document are met.  When NetBackup Enterprise Server 6.5.4 is released, please visit the following link for download and readme information:  
 http://www.symantec.com/enterprise/support/downloads.jsp?pid=15143

Until the formal resolution to this issue is available, Symantec strongly recommends implementing the Workaround listed in the next section of this TechNote.

Workaround:

For NetBackup 6.5, 6.5.1, 6.5.2, 6.5.2a, 6.5.3 and 6.5.3.1

To successfully backup the DFSR data, a registry key needs to be created and configured, and the DFS Replication service prior must be stopped prior to starting a backup.  

Creating the registry key: To disable the DFSR writer in the registry, do the following:

1. Launch the registry editor (Start, Run, regedit)

2. Navigate to the HKEY_LOCAL_MACHINE\SOFTWARE\Veritas\Symantec\BEDS\Engine\Shadow Copy Components

3. Add a new registry key called "Additional Not Authorized Writers" (without the quotation marks)

4. Inside the new Additional Not Authorized Writers key, create a REG_SZ value named "DFSR" and give it the value "{2707761b-2324-473d-88eb-eb007a359533}" (both without the quotation marks.  

NOTE: Disabling the DFSR writer in the registry only affects NetBackup.  It has no impact on the normal behavior of the server.  

Once the  registry key and value are created, stop the "DFS Replication" service before the backup start.  See the NetBackup Administration guide (under Related Documents below) for use of bpstart_notify.bat and bpend_notify.bat to automate this process.  Additionally, when attempting a restore, this service must be stopped as well.  

NOTE: By stopping the DFSR service, the backup succeeds, but when the data is restored, it is an AUTHORITATIVE restore at the system where the restore is done.  So items restored become the "master" copies.  This may be correct for most cases but may prompt replication when services are started.

In versions of NetBackup prior to NetBackup 6.5, the DFSR writer was ignored and shadow copy backup did not include Shadow Copy Components:\User Data. The DFS file share backup was accomplished during the file system backup.  This works in most cases, but if the files are in the process of replicating when the backup occurs, the backups may be corrupt, and as such, can not be restored.  

For NetBackup 5.0, 5.1 and 6.0, to prevent the backup from becoming corrupt, stop the "DFS Replication" service before the start of the backup.  It is not necessary to create the registry key as in NetBackup 6.5.  See the NetBackup Administration guide (under Related Documents below) for use of bpstart_notify.bat and bpend_notify.bat to automate the process of stopping and starting the DFS Replication service.  Additionally, when attempting a restore, this service must be stopped as well.  

NOTE: By stopping the DFSR service, the backup succeeds, but when the data is restored, it is an AUTHORITATIVE restore at the system where the restore is done.  So items restored become the "master" copies.  This may be correct for most cases but may prompt replication when services are started.

1. Always perform a Full backup prior to and after any changes to your environment.

2. Always make sure that your environment is running the latest version and patch level.

How to Subscribe to Software Alerts:
If you have not received this TechNote from the Symantec Email Notification Service as a Software Alerts, please subscribe at the following link:
 http://maillist.entsupport.symantec.com/subscribe.asp