Linux command nfsiostat can be used to determine the average Round Trip Time (avg RTT) in milliseconds which is a good measurement for storage performance issue. The nfsiostat command is available in later versions of the nfs-utils package
What does nfsiostat output mean?
The nfsiostat gets input from /proc/self/mountstats and provides information about the input/output performance of NFS shares mounted in the system.
We usually run this command this way nfsiostat 3 /mountpoint. 3 means 3s. It is the interval.