Several versions of the VMFS file system have been released since its introduction. ESXi supports VMFS3, VMFS5, and VMFS6.

For all VMFS version, ESXi offers complete read and write support. On all versions of VMFS, you can create and power on virtual machines.

Table 1. Host Access to VMFS Versions
VMFS6 Read and write
VMFS5 Read and write
VMFS3 Read and write
Note: You can continue to use existing VMFS3 datastores, but you cannot create new ones. If you have existing VMFS3 datastores, migrate virtual machines to the VMFS6 datastore.
The following table compares major characteristics of VMFS5 and VMFS6. For additional information, see Configuration Maximums .
Table 2. Comparing VMFS5 and VMFS6
Features and Functionalities VMFS5 VMFS6
Access for ESXi 6.5 hosts Yes Yes
Access for ESXi hosts version 6.0 and earlier Yes No
Datastores per host 512 512
512n storage devices Yes (default) Yes
512e storage devices Yes. Not supported on local 512e devices. Yes (default)
Automatic space reclamation No Yes
Manual space reclamation through the esxcli command. See Manually Reclaim Accumulated Storage Space. Yes Yes
Space reclamation from guest OS Limited Yes
GPT storage device partitioning Yes Yes
MBR storage device partitioning Yes

For a VMFS5 datastore that has been previously upgraded from VMFS3.

Storage devices greater than 2 TB for each VMFS extent Yes Yes
Support for virtual machines with large capacity virtual disks, or disks greater than 2 TB Yes Yes
Support of small files of 1 KB Yes Yes
Default use of ATS-only locking mechanisms on storage devices that support ATS. See VMFS Locking Mechanisms. Yes Yes
Block size Standard 1 MB Standard 1 MB
Default snapshots VMFSsparse for virtual disks smaller than 2 TB.

SEsparse for virtual disks larger than 2 TB.

Virtual disk emulation type 512n 512n
vMotion Yes Yes
Storage vMotion across different datastore types Yes Yes
High Availability and Fault Tolerance Yes Yes
DRS and Storage DRS Yes Yes
RDM Yes Yes
When you work with VMFS5 and VMFS6 datastores, consider the following:
  • Upgrade. After you upgrade your ESXi hosts to version 6.5, you can continue using any existing VMFS5 datastores. To take advantage of VMFS6 features, create a VMFS6 datastore and migrate virtual machines from the VMFS5 datastore to VMFS6 datastore. You cannot upgrade the VMFS5 datastore to VMFS6.
  • Datastore Extents. A spanned VMFS datastore must use only homogeneous storage devices, either 512n or 512e. The spanned datastore cannot extend over devices of different formats.
  • Block Size. The block size on a VMFS datastore defines the maximum file size and the amount of space a file occupies. VMFS5 and VMFS6 datastores support the block size of 1 MB.
  • Storage vMotion. Storage vMotion supports migration across VMFS, vSAN, and Virtual Volumes datastores. vCenter Server performs compatibility checks to validate Storage vMotion across different types of datastores.
  • Storage DRS. VMFS5 and VMFS6 can coexist in the same datastore cluster. However, all datastores in the cluster must use homogeneous storage devices, either 512n or 512e. Do not mix devices of different formats within the same datastore cluster.