Upgrading datastores to VMFS-5

With vSphere 5, VMware upgraded the VMFS filesystem to version 5. VMFS-5 came with the following new features: Unified 1MB File Block Size, Large Single Extent Volumes of 64 TB, Smaller 8 KB Sub-Block, Small File Support, Increased File Count limit > 120,000, VMware vSphere Storage APIs for Array Integration (VAAI), primitive Atomic Test & Set (ATS), enhancement for file locking, GUID Partition Table (GPT), and a new starting sector of 2048.

If you upgraded your vSphere environment from version 4 or earlier to version 5, your datastores are probably still on VMFS-3. There are two options for going to VMFS-5. The first option is to create new VMFS-5 datastores and move your virtual machines to the new datastores. When your old VMFS-3 datastores are empty, you can remove them. The advantage of this method is that the new datastores will have all of the new VMFS-5 features. However, it is a lot of work and you need enough free space on your storage system...