ESXi supports NFS protocols version 3 and 4.1. To support both versions, ESXi uses two different NFS clients.

Comparing Versions of NFS Clients

The following table lists capabilities that the NFS version 3 and 4.1 support.

Characteristics NFS version 3 NFS version 4.1
Security mechanisms AUTH_SYS

AUTH_SYS and Kerberos (krb5 and krb5i)

Encryption algorithms with Kerberos N/A AES256-CTS-HMAC-SHA1-96 and AES128-CTS-HMAC-SHA1-96
Multipathing Not supported Supported through the session trunking
Locking mechanisms Propriety client-side locking Server-side locking
Hardware acceleration Supported Supported
Thick virtual disks Supported Supported
IPv6 Supported Supported for AUTH_SYS and Kerberos
ISO images presented as CD-ROMs to virtual machines Supported Supported
Virtual machine snapshots Supported Supported
Virtual machines with virtual disks greater than 2 TB Supported Supported

NFS Protocols and vSphere Solutions

The following table lists major vSphere solutions that NFS versions support.

vSphere Features NFS version 3 NFS version 4.1
vMotion and Storage vMotion Yes Yes
High Availability (HA) Yes Yes
Fault Tolerance (FT) Yes Yes
Distributed Resource Scheduler (DRS) Yes Yes
Host Profiles Yes Yes
Storage DRS Yes No
Storage I/O Control Yes No
Site Recovery Manager Yes No
Virtual Volumes Yes Yes
vSphere Replication Yes Yes
vRealize Operations Manager Yes Yes

NFS 4.1 and Fault Tolerance

Virtual machines on NFS v4.1 support the new Fault Tolerance mechanism introduced in vSphere 6.0.

Virtual machines on NFS v4.1 do not support the old, legacy Fault Tolerance mechanism.

In vSphere 6.0, the newer Fault Tolerance mechanism can accommodate symmetric multiprocessor (SMP) virtual machines with up to four vCPUs. Earlier versions of vSphere used a different technology for Fault Tolerance, with different requirements and characteristics.

NFS Upgrades

When you upgrade ESXi to version 6.5, existing NFS 4.1 datastores automatically begin supporting functionalities that were not available in the previous ESXi release. These functionalities include Virtual Volumes, hardware acceleration, and so on.

ESXi does not support automatic datastore conversions from NFS version 3 to NFS 4.1.

If you want to upgrade your NFS 3 datastore, the following options are available:

  • Create the NFS 4.1 datastore, and then use Storage vMotion to migrate virtual machines from the old datastore to the new one.
  • Use conversion methods provided by your NFS storage server. For more information, contact your storage vendor.
  • Unmount the NFS 3 datastore, and then mount as NFS 4.1 datastore.
    Caution: If you use this option, make sure to unmount the datastore from all hosts that have access to the datastore. The datastore can never be mounted by using both protocols at the same time.