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 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.
