Recommended options when connecting to NAS or Linux servers

When you are creating a new NFS connection to a Linux server or a typical Linux-based NAS device (Network Attached Storage), we recommend the following NFS options as a good starting point:

nosuid, bg, tcp, resvport, intr, locallocks, nfc

After creating a new mount or automount entry, you can modify the defaults as follows to achieve this combination of settings:

1. Disable the option Mount as read-only.
2. Click the button Show advanced options.
3. Enable the option File System > File system handling: Allow hanging operations to be canceled without server response.
4. Disable the option File System > File system handling: Allow operations to fail if server doesn’t respond.
5. Switch to Communication > Transport protocol: TCP.
6. Enable the option Special Features > Locking operations: Lock on the client instead of on the server.
7. Enable the option Special Features > Character encoding: Process all names as Unicode Normalization Form C (NFC).

This should only be seen as “best practice” when creating a new entry. Due to the wide variety of Linux distributions and NAS implementations, it can be necessary to alter other options as well.

You must not change the NFC option for mount definitions that already exist and where you have created files from your Mac on the NFS server already. This could otherwise corrupt file names on the server.

Special notes on macOS 14 Sonoma

The Finder of macOS 14 is immature and unfortunately often shows serious errors related to file locks. These errors can indirectly cause the entire operating system to hang when using NFS. For this reason, we recommend to turn off client-side file locks completely when using NFS on macOS 14 Sonoma. Replace item (6) in the list above with:

• Enable the option Special Features > Lock operations: Disable NFS file locking.

This means the recommended option list for this case changes to:

nosuid, bg, tcp, resvport, intr, nolocks, nfc