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Q233492: The Major Differences Between NFS Versions 2 and 3

Article: Q233492
Product(s): Microsoft Windows NT
Version(s): WINDOWS:2000; winnt:4.0 SP3,4.0 SP4
Operating System(s): 
Keyword(s): 
Last Modified: 10-AUG-2001

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The information in this article applies to:

- Microsoft Windows NT Server versions 4.0 SP3, 4.0 SP4, used with:
   - Microsoft Windows Services for UNIX, version 2.0 
- Microsoft Windows 2000 Professional, used with:
   - Microsoft Windows Services for UNIX, version 2.0 
- Microsoft Windows 2000 Server, used with:
   - Microsoft Windows Services for UNIX, version 2.0 
- Microsoft Windows 2000 Advanced Server, used with:
   - Microsoft Windows Services for UNIX, version 2.0 
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SUMMARY
=======

This articles discusses some major differences between Network File System (NFS)
version 2 and version 3.

NFS Version 2 is documented in RFC 1094 and was published in March 1989. NFS
Version 3 is documented in RFC 1813 and was published in June 1995.

MORE INFORMATION
================

NOTE: Services for Unix 2.0 supports both NFS versions 2 and 3.

The major differences between the NFS versions 2 and 3 are:

- Version 2 of the NFS protocol limited file offsets to a 32-bit quantity,
  which limited the size of files accessible by clients to 4.2 GB. For users
  who regularly gain access to larger files, this was a severe limitation. NFS
  version 3 extended the file offsets and a number of other fields to 64-bits.

- NFS Version 2 limited the data transfer size to 8 KB. No single read or write
  request could exceed 8 KB. This limits performance on high-bandwidth networks
  because it artificially increases the number of NFS requests to transfer a
  given amount of data. NFS version 3 removed that limitation and allows the
  client and server to negotiate a maximum transfer size.

- Version 2 NFS servers must commit data written by a client to stable storage
  (a disk or NVRAM) before responding affirmatively to the client.

- NFS version 3 provides a new COMMIT operation that allows a client to perform
  unstable writes to a server followed by a COMMIT request. The server is
  required to verify that client data is on stable storage only when it
  receives the COMMIT operation. A mechanism is provided that allows the client
  to detect server loss of uncommitted data and recover.

Additional query words:

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Keywords          :  
Technology        : kbWinNTsearch kbWinNTSsearch
Version           : WINDOWS:2000; winnt:4.0 SP3,4.0 SP4
Issue type        : kbinfo

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