It's hard to say for certain whether your configuration is supported without some additional details. It sounds like you're saying that the boot volume is remaining on NFS but Exchange databases and logs will move to fiber channel. Here is Microsoft's official support statement on storage:
The storage used by the Exchange guest machine for storage of Exchange data (for example, mailbox databases or Hub transport queues) can be virtual storage of a fixed size (for example, fixed virtual hard disks (VHDs) in a Hyper-V environment), SCSI pass-through storage, or Internet SCSI (iSCSI) storage. Pass-through storage is storage that's configured at the host level and dedicated to one guest machine. All storage used by an Exchange guest machine for storage of Exchange data (Exchange Binaries, Transaction Logs, Transport or Mailbox or Public Folder Databases) must be block-level storage because Exchange 2010 doesn’t support the use of non-block-level storage protocols, such as, but not limited to NFS or CIFS/SMB. The volumes must be block-level storage protocols from the storage device to the guest machine. It also isn’t supported to present a volume to a hypervisor using a non-block-level storage protocol, even if the hypervisor presents the volume to the guest machine as a block-level storage protocol.
The bold sections are mine. Note that Exchange Binaries must be on block based storage. That means that if you installed the Exchange binaries on the boot volume (for example) on NFS, but put databases and logs on fiber channel, you would still not be supported. You'd need to have a separate drive in Windows that is stored on block storage where you installed the Exchange binaries.
Similarly, notice that Transport (meaning transport queues on your Hub Transport Server) is listed as requiring block storage. You'll also need to make sure that you have your Hub Transport virtual machine drives allocated such that the queues end up on FC storage. The same is true for Edge Transport if you have that in your environment.
And if you think this is all too complicated, you can see why I normally tell customers to just put the entire Exchange virtual machine on block based storage so you don't have to worry about any of this nuance. If you have the space to do that I would recommend it since that will greatly simplify things in terms of support.
Finally, you're correct - use eagerzeroedthick disks for your Exchange VMs. That's actually another piece that is specifically called out by Microsoft and they explicitly state that thin provisioned disks are not supported. See below:
- Virtual disks that dynamically expand aren't supported by Exchange.
You can read both of the support statements that I quoted above at the following URL: Understanding Exchange 2010 Virtualization: Exchange 2010 Help
Hope that helps clears things up!
Matt