The following must be enabled on each site server:
Enable Network File System (NFS):
1. Add the Server Role “Server for NFS” under File and Storage Services > File and iSCSI Services.
The documentation to enable shows a different path based on Server 2008 that appears to no longer exists, so my above instructions do not mirror the following:
https://support.symantec.com/en_US/article.HOWTO92293.html
To Enable Network File System (NFS):
1. Open Server Manager on NBS Server
2. Open Roles > File Services
3. Add Role Services
4. Select "Services for Network File System"
5. Click Install and wait for the process to complete.