To discuss this subject, we need to understand NFS (Network File System) and VMFS (Virtual Machine File System) are different File Systems. NFS is a file level file system, and VMFS is a block level file system.
NFS, VMFS (here is included LUNs/Disks), vSAN and recently VVols (Virtual Volumes) are the type of Datastores that we can use in VMware.
A brief history of NFS and VMFS file systems.
NFS is a network file system that exists since 1984 and was developed by SUN Microsystems, and initial was only build and use for UNIX base.
Since 1984 there were many changes in the NFS. Version 1 used only internally in SUN development and then new version 2 had some changes and was starting spread out for other UNIX and Linux servers.
Middle 90’s NFS v3 arrives, and support for 64-bit file sizes and offsets and can now handle files larger than 2GB. NFS v3 extends to more UNIX/Linux servers and now also to NAS with storage vendors implementing NFS technology on their systems.
Mainly adopted by NetApp, a significant contributor that develop with SUN the next NFS version.
That is also when Windows systems are starting using NFS with Server Message Block [SMB], also known as CIFS.
Main version changes:
Important Note: With NFSv4.1 VMware doesn’t support these features:
(version still in discussion and still in development, even some of the features are already implemented)
Main Source: IETF
In vCenter when selecting an NFS Datastore, we can also check some of the above changes between versions.
Note: All changes regarding NFSv4 and next, can be tracked here in the NFS Working Group
NFS in VMware:
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.
On opposed to NFS, VMFS is a block level file system.
VMware created VMFS with the primary purpose to store Virtual Machines or snapshots. VMFS is a high-performance clustered file system for virtualization and can be shared between multiple ESXi hosts or VMs and can simultaneously write and read data to and from a single storage location.
In the earlier versions VMFS1 (was a flat file system with no directory structure) and v2, VMFS was created for an idea of Virtual Infrastructure (VI).
However only after VMFS3 (around 2006) is when VMFS was starting to go further with a directory structure in the file system, more improvements, and a more mature file system that will be used until vSphere 4.x.
After vSphere 5.x a new VMFS5 version (arrives around 2011) improves most of the v3 attributes and introducing many performance enhancements.
Main version changes:
VMFS3 (vSphere 3.x/4.x)
VMFS5 (vSphere 5.x/6.x)
VMFS6 (vSphere 6.5/6.7)
VMFS 5 and VMFS 6 can coexist. However, due to the changes done in VMFS 6 metadata structures to make it 4K aligned, you cannot inline/offline upgrade from VMFS5 to VMFS6.
You can check in here in VMware site the main differences between VMFS 5/6
Note: Most of the new features, maximums, and improvements between VMFS versions is bound to the vSphere version. Even in one version of vSphere is not support, the next version of VMFS have a new feature or improvement that is transported by vSphere itself.
In vCenter when selecting a VMFS Datastore, we can also check some of the above changes between versions.
Datastores that you deploy on block storage devices use the vSphere Virtual Machine File System (VMFS) format. VMFS is a special high-performance file system format that is optimized for storing virtual machines
Like we stated above, VMFS is a block level file system, while NFS is a file level file system.
When creating a VMFS Datastore, the VMFS file system is created by the vSphere, while the NFS file system is on Storage side and is only mounted has a shared folder on the vSphere.
In the next image, we can see how each Datastore type access to Virtual Machines using a different type of network connectivity.
Next, we can check features and options that VMS and NFS can provide when used in VMware.
The final question is, is VMFS or NFS Storage better for your VMware Environment?
In my opinion, both file systems are mature enough to use in VMware. But, It always depends on the needs of your VMware environment. Analyzing Storage management features enabled and the final pros and cons, then you can decide what it fits best in your environment.
However, moving to NFS4.1 now is something that is on hold for many companies when using VMware environment, since there are some restrictions that we enumerated above.
When there is a need of use of shared folders CIFS (to Windows or store users home directories), then the choice is NFS. If not, you need to create a File Server to provide shared folders and the access/permissions to those files/folders.