An NFS client built into ESXi uses the Network File System (NFS) protocol over TCP/IP to access a designated NFS volume that is located on a NAS server. The ESXi host can mount the volume and use it for its storage needs. vSphere supports versions 3 and 4.1 of the NFS protocol.

Typically, the NFS volume or directory is created by a storage administrator and is exported from the NFS server. You do not need to format the NFS volume with a local file system, such as VMFS. Instead, you mount the volume directly on the ESXi hosts and use it to store and boot virtual machines in the same way that you use the VMFS datastores.

In addition to storing virtual disks on NFS datastores, you can use NFS as a central repository for ISO images, virtual machine templates, and so on. If you use the datastore for the ISO images, you can connect the CD-ROM device of the virtual machine to an ISO file on the datastore. You then can install a guest operating system from the ISO file.

After you set up NFS storage environment, see the following topics to create and manage NFS datastores:

NFS Protocols and ESXi

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


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 Site Recovery Manager does not support NFS 4.1 datastores for array-based replication and Virtual Volumes replication. You can use Site Recovery Manager with NFS v 4.1 datastores for vSphere Replication.
Virtual Volumes Yes Yes
vSphere Replication Yes Yes
VMware Aria Operations Yes Yes

NFS 4.1 and Fault Tolerance

Virtual machines on NFS 4.1 support the new Fault Tolerance mechanism that was introduced in vSphere 6.0. The mechanism can accommodate symmetric multiprocessor (SMP) virtual machines with up to four vCPUs.

NFS 4.1 VMs do not support the legacy Fault Tolerance mechanism.

NFS Upgrades

When you upgrade ESXi from a version earlier than 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.