There are a number of socket options that can greatly affect the performance of a TCP-based server like Samba.

The socket options that Samba uses are settable both on the command line with the -O option and in the smb.conf file.

The socket options section of the smb.conf manual page describes how to set these and gives recommendations.

Getting the socket options correct can make a big difference to your performance, but getting them wrong can degrade it by just as much. The correct settings are very dependent on your local network.

The socket option TCP_NODELAY is the one that seems to make the biggest single difference for most networks. Many people report that adding socket options = TCP_NODELAY doubles the read performance of a Samba drive. The best explanation I have seen for this is that the Microsoft TCP/IP stack is slow in sending TCP ACKs.

There have been reports that setting socket options = SO_RCVBUF=8192 in smb.conf can seriously degrade Samba performance on the loopback adaptor (IP Address 127.0.0.1). It is strongly recommended that before specifying any settings for socket options , the effect first be quantitatively measured on the server being configured.