NFS, specifically NFSv3, as VMware uses it, is a network protocol for accessing files over the network. It allows a remote server to share files with a client. In the case of VMware, we are accessing the various VMware files on a remote data store. VMs are stored on the remote datastore in VMX, VMDK files, and various log, cache, and configuration files.
NFSv3 operates on UDP. UDP protocols do not inherently have a retransmit or packet drop detection in place. As such, we need to ensure our NFS network is reliable and free of packet loss. NFS will retransmit lost packets but will at least double the latency of file operations. The UDP protocol allows NFS to operate with minimal overhead and performance loss over the network.
NFSv3 has the following network requirements:
Reliable local network free of packet drops
Fast local network (at least 1 Gbps, ideally 10 Gbps)
Low latency (in the ideal case, no more than one or two network hops away)
ESXi hosts should be on the same subnet as the NFS...