How to configure hard or soft NFS mount options

An NFS mount option controls what local applications experience when a remote export stops answering. hard keeps retrying requests until the server responds again, while soft lets the client return an error after its retry limit; the choice matters most for applications that write data or cannot tolerate blocked file access.

Linux stores persistent client mounts in /etc/fstab, native systemd .mount units, or an automounter map, and the live kernel mount table shows what the client actually applied. The common fstab entry uses the nfs filesystem type with a version option such as vers=4.2, even though the active table may display nfs4 after the mount is established.

Changing hard to soft is not a generic remount toggle. NFS-specific options usually require unmounting and mounting the export again, so make the change during a maintenance window, stop applications that are using the path, and confirm the live option after reconnecting.

1. Open a terminal on the Linux client that owns the mounted export.
2. Identify the active NFS mount and current failure behavior.

   $ findmnt --target /mnt/projects --types nfs,nfs4 --output TARGET,SOURCE,FSTYPE,OPTIONS
   TARGET        SOURCE                                FSTYPE OPTIONS
   /mnt/projects files.example.net:/srv/nfs/projects  nfs4   rw,relatime,vers=4.2,rsize=1048576,wsize=1048576,hard,proto=tcp,timeo=600,retrans=2

   Replace /mnt/projects with the client mount point. A live row with hard or soft shows the behavior currently applied by the kernel, not only the saved configuration.

3. Choose the behavior for the mounted workload.

   Use hard for writable, stateful, or integrity-sensitive data so operations wait for the server instead of returning partial I/O errors. Use soft only when client responsiveness is more important than data integrity, such as a read-only or disposable lookup path.

4. Edit the saved /etc/fstab entry for the mount point.

   $ sudoedit /etc/fstab

   If this mount is managed by a native systemd .mount unit or autofs map, update that controller's option list instead of /etc/fstab.

   Related: How to mount an NFS export with a systemd mount unit
   Related: How to automount an NFS export with autofs

5. Set exactly one failure behavior option in the entry.

   files.example.net:/srv/nfs/projects /mnt/projects nfs rw,_netdev,hard,vers=4.2,proto=tcp,timeo=600,retrans=2 0 0

   For a deliberate soft mount, replace hard,timeo=600 with soft,timeo=150 and keep retrans=2 explicit so the returned-error window is intentional. timeo is measured in tenths of a second, so 150 means 15 seconds. Current Linux ignores the legacy intr option.

6. Validate the saved mount table before disconnecting the current mount.

   $ sudo findmnt --verify --verbose
   /mnt/projects
      [ ] target exists
      [ ] VFS options: rw
      [ ] FS options: hard,vers=4.2,proto=tcp,timeo=600,retrans=2
      [ ] userspace options: _netdev
      [ ] do not check files.example.net:/srv/nfs/projects source (pseudo/net)
      [ ] do not check files.example.net:/srv/nfs/projects FS type (pseudo/net)
   Success, no errors or warnings detected

   If the output includes other entries, fix any syntax error before changing the live NFS mount.

7. Stop application services that read or write /mnt/projects.
8. Unmount the current NFS session.

   $ sudo umount /mnt/projects

   If umount reports that the target is busy, find and stop the process that still has files open before forcing the disconnect. A forced unmount can interrupt active writes.

9. Mount the entry again from the saved configuration.

   $ sudo mount /mnt/projects

10. Confirm the selected option is active in the live mount table.

    $ findmnt --target /mnt/projects --types nfs,nfs4 --options hard --output TARGET,FSTYPE
    TARGET        FSTYPE
    /mnt/projects nfs4

    Use --options soft in the same command when the saved entry uses soft. No row means the live mount does not currently carry the selected option.

11. Read the mounted directory after reconnecting.

    $ ls /mnt/projects
    README.txt  reports

    If the directory listing fails, restore the previous saved options or troubleshoot server reachability before restarting dependent applications.
    Related: How to troubleshoot NFS mount timeouts
    Related: How to clean up a stale NFS client mount