Defrag is useful and desirable on a physical server, and as mentioned above, a pain in a virtual environment.  If you haven't set up your R2 server with a contiguous fixed (nonmanaged) size page file, not defragging will inevitably result in a hugely fragmented page file which will impact paging and system performance.  The one time I do a defrag in a virtual environment is as the final step to preparing a virtual machine template, but that's probably going a bit overboard.
Hey guys,  what are your personal opinions about defrag the volume/s on a Windows Server 2008 R2 x64 with Remote Desktop Services enabled?  Do you think it makes sense because of performance reasons?  Would you judge this different if it comes to VDI in conjunction with Windows XP/7?  Thanks Holger
Windows Server 2008 R2 and defrag