I've been reading up on the difference between fixed and dynamic sized disks when related to Hyper-V 2008 R2.
The blog consensus appears to be do not put your exchange on dynamic disks. What I am thinking to work around this problem is virtualised small business server 2011 with a fixed C drive for the OS, fixed 100 gig D drive to store exchange and SharePoint information. Then create a 600 GB dynamic disk to store the clients word documents etc.
The client only has around 80 GB of data (of the word, excel variety). Currently I have been testing the small business server with fixed disks across the board. What this means is the bare metal backup from the Hyper-V host is taking forever because there is a 600 gig disc that only contains 80 gig of actual data.
To cut a long story short I would be running small business server on fixed disks with the exception of Word documents etc residing on a dynamic/thin provisioned disks.
The client has around 12 staff and the disk subsystem is a Dell PERC spinning six 450 gig 15 k SAS so throughput is pretty good.
Looking for thoughts on this from SBS and virtualisation experts