-i interval          Specifies the interval of time (in seconds)
                         to wait between updates to the statistical
                         information on display. The default interval
                         is 4 seconds.
    -s                   Displays server NFS and RPC information.
    -n                   Displays NFS information.
    -r                   Displays RPC information.
    -2                   Displays NFS version 2 statistics.
    -3                   Displays NFS version 3 statistics.
    -z                   Reinitializes the statistics. Use this flag
                         to set NFS statistics to zero. You must
                         have system management or system operator
                         privileges to use this flag.