Using Offline Files on DFS Shares / all shares are going offline!

What happend? You only made 1 DFS Target available offline, but all of the shares are offline when Slow Link is detected or the File Server is down.

Consider the following Scenario:

You configured a DFS Root in the \\Domain Contoso.com\Public

the Targets are:

Offline on the File Server \\Server_1;
Nosync on the File Server \\Server_2;
Sales on the File Server \\Server_3;

on the Vista / Windows 7 Clients you map the Drives as follows:

O:\Offline
N:\Nosync
S:\Sales

You make available offline the mapped drive O:\Offline

Now it happends, the Server \\Server_1 is down and the share offline is not accessible anymore

You will notice that all the mapped drives O;N;S are offline and not accessible anymore even though the other Servers are reachable via Ping

Here is the Reason:

The Offline Files feature does not distinguish DFS paths from UNC paths. This can cause the Vista / Windows 7 client to interpret the entire namespace as unavailable if a target is down when a Vista / Windows 7 client attempts to access it. For example, if \\Contoso.com\Public is a domain-based root with several root targets and numerous links, the Offline Files feature interprets this namespace as a single server named \\Contoso.com. If a client is accessing or attempts to access the target Offline in the \\Contoso.com\Public namespace, and the target is unavailable, the Vista / Windows 7 client interprets the entire namespace as unavailable and will attempt to open a user’s locally cached files (if they exist). The Vista / Windows 7 client cannot access any target (in our example: Nosync & Sales & Offline) in the namespace until the target comes back online. The Vista / Windows 7 client will check every 2 minutes to detect whether the target has come back online.

What to do to avoid this:

- Use the NetBIOS Name or FQDN of the Target Server for mapping the Offline Files Share