According to this Phoronix article, Linux should support the birth time attribute in the NFS server since 5.18. However, it doesn’t show up in the stat output when looking at the file through the NFS mount, or elsewhere (at least, the Dolphin file browser and also a macOS client):
% stat file
File: file
Size: 0 Blocks: 0 IO Block: 1048576 regular empty file
Device: 0,70 Inode: 103416894 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 1000/ saiko) Gid: ( 100/ users)
Access: 2023-12-17 03:22:45.368950609 +0100
Modify: 2023-12-17 03:22:45.368950609 +0100
Change: 2023-12-17 03:22:45.368950609 +0100
Birth: -
What gives? Running stat on the server directly, it shows the attribute. The backing file system is ext4, kernel 6.5.12. The client is using kernel 6.1.63.
Simple thing, but are you sure you mounted the NFS share as NFSv4? I don’t have access to a machine to check right now, but I think it might default to mounting NFSv3, even if both sides support v4.
It is NFS4:
vineta.h.kfe.pt:/nfs/nas on /nfs/nas type nfs4 (rw,relatime,vers=4.2,rsize=1048576,wsize=1048576,namlen=255,soft,proto=tcp6,timeo=600,retrans=2,sec=krb5p,clientaddr=2001:470:7391::ce,local_lock=none,addr=2001:470:7391::c0,_netdev)