This is an old revision of the document!
https://www.slashroot.in/how-do-linux-nfs-performance-tuning-and-optimization
http://nfs.sourceforge.net/nfs-howto/ar01s05.html
apt -y install nfs-common
NFSv4 handles UID maping differently than NFSv3.
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 cat /etc/idmapd.conf nfsidmap -cv # clear cache