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NOTE: This is a work in progress, the final result will be forthcoming soon.


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.


According to the site the answer is “ Other restrictions that have been eliminated in the NFS v3 server include the file storage size can exceed 2-gigabytes and data transfers can exceed 8 KB.”

This probably means that the NFS client is still running V2. So if you are using the NFS client you are likely bound to 2 GB, while the NFS server can exceed 2 GB.


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.1549914606.txt.gz · Last modified: 2019/02/11 19:50 by mmacgregor