Transparent Caching causing permanent WAN-Traffic

Question

Hello,
we enabled Windows 7 Transparent Caching in one of our branch offices via Group Policy.
We limited the Cache Size to 5GB and max file size 512MB. The branch office uses a central fileserver connected via a 2x2Mbit Link (MPLS). During the course of the week, we observed high bandwidth usage after we enabled Transparent Caching on the Clients. Digging
deeper into the problem we used network sniffers and procmon from sysinternals to see what is going on. We also connected to several clients that produced the traffic to see what the users were doing (copy jobs running?).
What we found out: The traffic was not unidirectional, but up and download bandwidth was EQUALLY eaten up. The clients had NO copy jobs running, just Outlook, Word and Excel open with no file transfer going out through these applications.
The users also had some Windows Explorers open and these showed a directory listing of the remote fileservers they were working with. After we closed the Windows Explorer windows, the traffic immediately stopped!
Through network sniffing we found out that the explorer process was constantly pulling directory data from the remote fileserver. So you see a SMB request packet from the client and then a packet with a filename from the remote fileserver. Looks like a directory
traversing. You see also that these files (or at least some KB from them) are written to the C:\windows\csc directory structure. I first tought about the search indexer, but this should not touch network drives by default. But even more strange is that this
traffic stops immediately when the explorer windows are closed.
What is this and how can this be avoided?

Answer 1

Hi,
How do you configure Offline files? What's your "Configure Background Sync" settings?
Background Sync is a machine-specific setting which applies to any user who logs on to the specified computer while this policy setting is in effect. This policy setting is in effect when a network folder is determined to be in “slow-link” mode, as specified
by the “Configure slow-link mode” policy setting.
If your fileserver make big change constantly, you may need to update the list of directory paths that the functionality can be enabled for.
To provide data integrity, Windows 7 always contacts the server to ensure that the cached copy is up to date.
For detailed information to check, please refer to the following article:
Configuring New Offline Files Features for Windows 7 Computers Step-by-Step Guide
http://technet.microsoft.com/en-us/library/ff633429(v=ws.10).aspx
Best regards,
Karen Hu
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