A mount -t nfs fails with Stale file handle if the server has some stale exports entries for that client. You can check for this via looking at /proc/fs/nfs/exports or /proc/fs/nfsd/exports . If there is entry for the client it might be a stale one.
How do I fix a stale NFS file handle?
Try restarting NFS first on the server and then on the clients. This may clear the file handles. Rebooting NFS servers with files opened from other servers is not recommended. This is especially problematic if the open file has been deleted on the server.
How do I delete a stale NFS file handle?
Specify the -f option to the umount  command to forcibly unmount a filesystem. This should be done only as a last resort, since using this option can cause data loss for open files.
What does stale file handle mean?
A file handle becomes stale when the file or directory referenced by the handle is removed by another host/server, while our client still holds an active reference to the object file/directory.
Where can I find stale NFS mounts?
Stale files are usually found using ls -ltR /<mounted directory path> | grep “?” , but this usually takes some time (since it goes over all files in a given path). To further clarify, the issue seen in specific files such as Java library file(s) rather than the whole mount.
What causes NFS stale file handle?
A filehandle becomes stale whenever the file or directory referenced by the handle is removed by another host, while your client still holds an active reference to the object. … So this can occur if the directory is modified on the NFS server, but the directories modification time is not updated.
What causes NFS files?
Cause. Under UNIX, if you remove a file that a currently running process still has open, the file isn’t really removed. … Once you have located and killed the process that has the file open, the . nfs file will go away automatically.