What type of SAN are you using? Do you have the partitions that the database and logs are residing are on the VM’s vmdk files or exposed directly to the SAN? I normally recommend having the base OS associated with the VM’s vmdk files and then expose the VM’s directly to the SAN either via iSCSI or dedicated fibre or RDM.#
I agree with the above statement
i wouldnt run your exchange data stores or logs within a vmdk
create a couple of RDM’s and use those
then maybe just snapshot the vmdk (I cant remember whether vizioncore quiesces the vmdk (VSS) i think it does, but wont backup the RDM’s) you really need an application aware snapshot utility, i.e. snapmanager for Exchnage – i have tested exchange with simple non application aware snapshots and was able to recover and mirror what should have been a crash consistent database without any issues.