====== NFS - Network File System ======

  * NFS is a network file sharing protocol like SMB/CIFS
  * NFS allows multiple users to mount the same filesystem over a network
  * NFS works well with the Citrix Hypervisor (XenServer) and XCP-ng hypervisors
  * NFS is simpler to manage than iSCSI (block storage)
    * May use bonding for higher availability
  * iSCSI may offer better performance
    * May use MPIO for higher availability

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 =====

<file>
apt -y install nfs-common
</file>

===== Troubleshooting =====

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

<note tip>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.</note>

<note warning>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).</note> 

<file>
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'
</file>

<file>
ps aux | grep idmapd

vim /etc/idmapd.conf

Domain = somedomain.tld

nfsidmap -cv   # clear cache
</file>