LHS Feature Of The Week #2 - Remote Differential Compression

[Update: Added link to RDC Whitepaper and blurb about RDC dogfooding in DFS Replication (thanks cfsbloggers)]

Hello everyone, and welcome to the second installment of the “Feature Of The Week” newsletter. This week, we will take a short little peek at a feature coming in Vista and Longhorn Server called Remote Differential Compression.

So, sit back, relax, and enjoy the Longhorn Server Feature Of The Week!

What is Remote Differential Compression? Remote Differential Compression (RDC) allows applications to synchronize data between two computers in an efficient manner. The synchronization efficiency is made possible by using compression techniques to minimize the amount of data sent across the network.

What makes RDC different from other differencing mechanisms? RDC is different from patching-oriented differencing mechanisms, such as Binary Delta Compression (BDC), which are designed to operate only on known versions of a single file. RDC makes no assumptions about file similarity or versioning. Because differences between files are computed on the fly, RDC is ideally suited for synchronizing files that are different or have been updated independently.

What scenarios does this enable? RDC is suitable for applications that move data across a wide area network where the data transmission costs outweigh the CPU cost of signature computation. RDC can also be used on faster networks if the amount of data to be transferred is relatively large and the changes to the data are typically small.

Dogfooding RDC. It's important to note that we are actively dogfooding RDC internally. One of the current examples of that dogfooding is that RDC is actively being used for DFS Replication, available on Windows Server 2003 R2.

Resources

• Documentation
  • Windows SDK
  • Using Remote Differential Compression
  • RDC Whitepaper
• Code 
  • If you have the latest Windows SDK installed, you can find a simple Client/Server example using RDC in the following directory: %INSTALL_DIR%\Samples\winbase\RDC

Enjoy!

[Crosspost from Managed World]

Comments

• Anonymous
  November 14, 2006
  You might want to mention that RDC is used for DFS Replication, introduced in Windows Server 2003 R2. If anyone wants the nitty-gritty details of RDC, check out the whitepaper at  http://research.microsoft.com/research/pubs/view.aspx?type=Technical%20Report&id=1203.

• Anonymous
  November 15, 2006
  Ah, I'm glad you guys found the place. Excellent point. I will go ahead and update the post. Thanks!