Services for UNIX

Supported Versions of NFS

Two versions of NFS are available: version 2 (described in RFC 1094) and version 3 (described in RFC 1813).

Version 2 includes the following features and limitations:

4 GB. File size indicator limited to 32-bits.
Network transport using User Datagram Protocol (UDP) or Transmission Control Protocol (TCP).
NFS packet size limited to a maximum of 8 kilobytes (KB).
A file-write packet must be committed to disk before the server sends an acknowledgement.

Version 3 includes the following features and limitations:

File size indicator limited to 64-bits.
Network transport using TCP or UDP.
Maximum packet size is 64 KB with UDP.
Packet size determines the number and frequency of client/server exchanges and acknowledgements.
Server can cache client write requests unless the client requests that the write request be written to disk.

NFS version 3 uses TCP as its network transport, if TCP is supported by both the client and the server. TCP has the advantage of being more reliable than UDP, but it must maintain state, so it may provide less performance in certain circumstances