Some quick questions and answers - Hyper-V and Failover Clustering
1) Should you use different LUN for each VM?
If you are using Windows Server 2008 (not R2) you should configure one LUN per VM so that you won’t bring down all VMs on that LUN in case of a migration or a failover. I you`re running 2008 R2 you have the possibility to use CSV – that let you place every VM (if you want to) on a single LUN. CSV also supports Live Migration – migrate your VMs with no downtime or interruption.
2) Should I use Pass-Through disks?
When it comes to Pass-Through disks, I would rather recommend using Fixed-Sized disks (.VHD). The performance is almost equal and you have much more flexibility when it comes to managing that VM with its disk. It`s also simplifies backups and restores of VMs.
3) Would it be recommended to put all OS disks (the IDE .VHDs) from all VMs on one LUN/CSV?
For the location of the VMs OS-partition (ide), I often place them on a dedicated CSV/LUN, and place the VMs data-partition on another CSV LUN. One tip could be to place the I/O intensive vhds on a SAS LUN and the other vhds on SATA LUN (if you have a SAN with that configuration.
4) How is the heartbeat NIC configured?
In an ideal world - the heartbeat should be placed on a separate network. But sometimes the ideal is not always possible and you could also have this heartbeat on shared networks (LAN etc.)