chadmichael wrote:
How can that be shared then? Wouldn't it cause data corruption to have two hosts with block level access to a given device?
For most operating systems and filesystems, that wouldbe true. However, some filesystems / cluster systems are design with this sort of multi-access in mind, and prevent corruption of the type you are thinking with clever use of locking mechanisms, etc.
VMFS and ESXi/vSphere is one of those combinations. VMFS is designed as a clustered filesystem, and can handle many hosts accessing the same volume.