Tech tip: Volume Shadow Copy Services (Vss) on Window Server 2008 can make a copy of active, open files on the fly. It works on the block level similarly to an open file agent. This works a treat if you need a quick-and-dirty command line backup.
To make a copy of the (C:) volume:
C:\> vssadmin create shadow /for=c:
To view copies of the (C:) volume:
C:\> vssadmin list shadows /for=c:
To mount a shadow copy as a browseable folder:
C:\>mklink /d <folder name> <shadow copy volume from list>
C:\>mklink /d C:\mycopy \\?\GLOBALROOT\Device\HarddiskVolumeShadowCopy6
For more information, see:
http://technet.microsoft.com/en-us/library/cc754968(WS.10).aspx