Well, the EVA does not care. A single virtual disk that is only 1 GigaByte big can be spread over all disks in a disk group, even if the group has the maximum size of 240 disk drives.
If you split into 2 virtual disks, you can assign both to different controllers to use their CPU and cache memory.
Having many, many VMFSes might not be a good idea, because you will have much scattered free space. Do you remember the times when servers had multiple smaller disks and you had to move data around, because there was always ample space free on the wrong[/b] disk?
