Please can someone help clear this up for me? When a volume shadow copy snapshot is taken for the first, time what actually happens? My understanding is that each time a new snapshot is taken since the first one; only differential changed blocks are stored in the cached area. Now this makes sense, however the first snapshot has nothing to refer to, therefore I would expect the first one to be bigger. Many thanks

Hi, See this article: http://technet.microsoft.com/en-us/library/cc785914(WS.10).aspx The Volume Shadow Copy you mentioned here is differential, which means it is copy-on-write. The VSS will grow up when changes are made, so the first snapshot refer to the current data and before it is changed, the orignial data is written to differential area as a backup. The explanation: When a change to the original volume occurs, but before it is written to disk, the block about to be modified is read and then written to a “differences area”.Shaon Shan |TechNet Subscriber Support in forum |If you have any feedback on our support, please contact tngfb@microsoft.com