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How large of a file can my OpenVMS NFS server and/or client handle?


The answer depends on which IP stack you are running on your OpenVMS machine and which version of Network File System (NFS) is installed. 2 gigabytes was a major power of 2 boundary for almost all of the IP stacks. NFS v2 had that limitation because it only used 32 bits. Since one of the bits was signed, that means 2^31 power or 2,147,483,648 bytes. NFS v3 allowed files to exceed 2 GB because it utilized 64 bits of space. However, each vendor implemented this in different ways (ie, perhaps Server only and not the Client). So here is the information that we've been able to track down for each vendor.


It appears that in version 5.6, the NFS Server was upgraded to allow NFS v3. It is unclear what version the Client was upgraded to NFS v3, but version 6.0 definitely supports it. Thus, the best guess is as follows:

Pre-5.6 versions: NFS v2 only, thus limited to 2 gigabytes.

6.0 and above: NFS v3 is available for both client and server

Between those versions the server is not limited to 2 gigabytes, but the client is limited to that size.


According to the site the answer is “support for 64-bit file sizes and offsets, to handle files larger than 2 gigabytes”

Version 5.4 only mentions NFS v2. So if you are running V5.4 or earlier, the answer is 2 GB. If you are running version V5.5 and later, the answer is “larger than 2 gigabytes”.

TCP/IP Services:

Here there are three different answers.

Prior to version 5.1 (including the UCX versions), only the NFS v2 was available. Thus, that was a 2 GB limit.

Starting in version 5.1 through TCPIP V5.7 ECO 1, the NFS Server could be v3, but the NFS client could only be v2. Meaning that the client had a 2 GB limit while the server did not.

Starting in version 5.7 ECO 2, the NFS v3 client was available. So it is possible to exceed the 2 GB limit now.

tcpip_nfs_-_how_large_of_a_file_can_my_nfs_server_or_client_handle.txt · Last modified: 2019/02/11 19:56 by mmacgregor

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