Transparent Caching

Transparent cache is a Windows 7 feature that if enabled allows cached copies of opened files to be kept on a local volume when the source files reside on network resources. This will speed up access to files stored on file servers on remote networks and can make a huge difference in WAN scenarios. In some ways, it is similar to the BranchCache feature but with transparent caching you do not need Windows Server 2008 R2 file servers hosting shared folders and it works on Windows 7 Professional as well, apart from the Windows 7 Enterprise and Ultimate editions.

The process of transparent caching is as follows:

  1. The user opens a file and a copy is stored in the local cache.
  2. If the file is opened for a second time, Windows 7 checks the file to ensure that the cached copy is up to date.
  3. If the local cached copy is not up to date, then Windows 7 opens the copy stored on the shared resource while, saving a copy in the local cache.
  4. When a user changes a file, Windows 7 writes the changes to the copy of the file stored on the shared resource.

When the shared resource is unavailable, the local cached copy is also unavailable. There is no sync mechanism as the Offline Files feature does. Transparent caching works on all files in a shared folder, not just those that you have configured to be available offline. Windows 7 triggers transparent caching when the round-trip latency value exceeds the amount specified in the Enable Transparency Caching policy.

To enable Transparent Caching, start the Local Group Policy Editor by typing gpedit.msc in the Start search text box and go to Computer Configuration\Administrative Templates\Network\Offline Files, double-click the Enable Transparent Caching Policy and select Enabled.