NFS version 4

NFS Version 4 is the latest protocol specification for NFS and is defined in RFC 3530.

While it is similar to prior versions of NFS, primarily Version 3, the new protocol provides many new functional enhancements in areas such as security, scalability, and back-end data management. These characteristics make NFS Version 4 a better choice for large-scale distributed file sharing environments.

Some of the NFS Version 4 protocol features include the following:

• Implementation change of NFS operations
• TCP requirement
• Integrated locking protocol
• Integrated mount support
• Improved security mechanisms
• Internationalization support
• Extensible attribute model
• Access Control List support

Note that the additional functionality and complexity of the new protocol result in more processing overhead. Therefore, NFS version 4 performance might be slower than with NFS version 3 for many applications. The performance impact varies significantly depending on which new functions you use. For example, if you use the same security mechanisms on NFS version 4 and version 3, your system might perform slightly slower with NFS version 4. However, you might notice a significant degradation in performance when comparing the performance of version 3 using traditional UNIX authentication (AUTH_SYS) to that of version 4 using Kerberos 5 with privacy, which means full user data encryption.

Also note that any tuning recommendations made for NFS Version 3 typically apply to NFS version 4 as well.