Recently VMware announced Vsphere 6.5 has introduced a new version of VMFS version 6 with lot of new enhancements. This topic will cover major difference between VMFS 5 and VMFS 6.
The upgrade process is slightly change, we can’t upgrade directly existing VMFS 5 volumes to VMFS 6. You have to plan and create new VMFS 6 datastores and migrate the existing VMFS 5 datastores VMs using storage vMotion. Once everything complete then ensure and deleting the VMFS 5 datastores.
Device Sector Formats and VMFS Versions
A sector is a subdivision of a track on a storage disk or device. Each sector stores a fixed amount of data. Traditional 512n storage devices have been using a native 512-bytes sector size. In addition, due to the increasing demand for larger capacities, the storage industry has introduced advanced formats, such as 512-byte emulation, or 512e. 512e is the advanced format in which the physical sector size is 4,096 bytes, but the logical sector size emulates 512-bytes sector size. Storage devices that use the 512e format can support legacy applications and guest operating systems.
When you set up a datastore on a 512e storage device, VMFS6 is selected by default. For 512n storage devices, the default option is VMFS5, but you can select VMFS6.
Automatic Space Reclamation
vSphere 6.5 has introduced automate the configuration of the VMFS UNMAP capability to check current setting or to Enable / Disable it. vSphere 6.5 APIs that have introduced which differ from the vsphere 5.x version.
How to Enable UNMAP setting
New vSphere API called UpdateVmfsUnmapPriority() which accepts the UUID of a VMFS 6 datastore as well as an unmapPriority property which can either be "low" which means it is enabled or "none" which means it is disabled.
VMFS UNMAP settings, there is a new property under the Datastore->Info->Vmfs object called UnmapPriority.
I hope this has been informative and thank you for reading!