• Larger single extent volume (64TB)
• Larger Virtual Machine Disks (VMDKs): 2TB – 512 bytes with a new unified 1MB block size
• More and smaller sub-blocks (8KB) to reduce the amount of stranded/unused space
• Improvements in performance and scalability via the implementation of the vSphere vStorage API for Array Integration (VAAI) primitive ATS (Atomic Test & Set) across all datastore operations.
vSphere 5.0 supports both VMFS versions 3 and 5. Therefore, it is not necessary to upgrade your VMFS volumes. However, customers can move to VMFS-5 to benefit from these features. A complete set of VMFS-5 enhancements can be found in the What’s New in vSphere 5.0 Storage white paper.
http://www.vmware.com/files/pdf/techpaper/VMFS-5_Upgrade_Considerations.pdf
