Direct NFS: Failed to set socket buffer size.wtmax=[1048576] rtmax=[1048576], errno=-1 on Solaris

This error occured on Solaris (SPARC) using Direct NFS (dNFS). The MOS Note is incomplete and only recommends to increase the send and receive buffers, but the solution is below:

/usr/sbin/ndd -set /dev/tcp tcp_xmit_hiwat 1056768
/usr/sbin/ndd -set /dev/tcp tcp_recv_hiwat 1056768
/usr/sbin/ndd -set /dev/tcp tcp_max_buf 2097152

To check the values, use:

/usr/sbin/ndd /dev/tcp tcp_max_buf
/usr/sbin/ndd /dev/tcp tcp_xmit_hiwat
/usr/sbin/ndd /dev/tcp tcp_recv_hiwat