Table of Contents

NFS - Network File System

https://www.slashroot.in/how-do-linux-nfs-performance-tuning-and-optimization

http://nfs.sourceforge.net/nfs-howto/ar01s05.html

https://help.ubuntu.com/community/HighlyAvailableNFS

Ubuntu

apt -y install nfs-common

Troubleshooting

NFSv4: https://www.suse.com/support/kb/doc/?id=000017244

If you are having root squash problems, you might be able to specify vers=3 as a client mount option to get around the issue.
NFSv4 handles UID maping differently than NFSv3. In NFS v4 with idmapd, the same username@domainname must be recognized by both sides, or it will be mapped to nobody (regardless of root squash). 
mount    # show client mount details

umount /path/mountpoint
mount -a
tail -30 /var/log/syslog

nfsidmap[nnnnn]: nss_getpwnam: name 'root@somedomain.tld' does not map into domain 'localdomain'
ps aux | grep idmapd

vim /etc/idmapd.conf

Domain = somedomain.tld

nfsidmap -cv   # clear cache