Using DFS Namespaces and Offline Files

Customers often ask about how DFS Namespaces interacts with Offline Files. I asked our new DFS Namespaces PM, Sanjoy Chatterjee, to introduce himself and explain the interaction.

I am Sanjoy Chatterjee, the new PM for the DFS group. My goal for posting on this blog is to clear up common customer questions and/or highlight certain points which might have escaped explicit documentation. Here is some information about how DFS Namespaces interacts with Offline Files.

By using the Offline Files feature, you can make shared folders that correspond to DFS root targets and link targets available offline to client computers running Windows XP Professional or Windows Server 2003. The Offline Files feature provides three settings for shared folders:

  • Only the files and programs that users specify will be available offline.
  • All files and programs on the share will be available offline.
  • No files or programs on the share will be available offline.

Offline settings for root targets and link targets are set on the individual shared folders that are specified as targets. Although link targets appear subordinate to root targets in the namespace, link targets do not inherit or otherwise use the offline settings set on root targets. In addition, if a root or link has multiple targets, and those targets have different offline settings, the client will use whatever settings are applied to the target to which the client connects. Therefore, it is important for administrators to apply offline settings consistently to all targets for a DFS root or link.

The Offline Files feature does not distinguish DFS paths from UNC paths. This can cause the client to interpret the entire namespace as unavailable if a target is down when a client attempts to access it. For example, if \Contoso.comPublic is a domain-based root with several root targets and numerous links, the Offline Files feature interprets this namespace as a single server named \ If a client is accessing or attempts to access a target in the \Contoso.comPublic namespace, and the target is unavailable, the client interprets the entire namespace as unavailable and will attempt to open a user’s locally cached files (if they exist). The client cannot access any target in the namespace until the target comes back online. The client will check every 10 minutes to detect whether the target has come back online. When the target comes back online, the client will synchronize the files with the server. However, if this attempted synchronization fails (because the Server State has been updated as well as the client state during offline operation), the target is flagged as “in conflict.” At this point, the user has to use the Synchronization Manager to resolve the conflict. In this phase, the user has a choice of going back online without synchronizing changes. Alternatively, the user can use the Synchronization Manager to attempt to synchronize the offline files with those stored on the network.