socket options = IPTOS_LOWDELAY TCP_NODELAY SO_SNDBUF=8192 SO_RCVBUF=8192 in smb.conf

I have set this socket option as one of the performance tuning configuration on my production samba server long ago in the 100M/bit network era. Many later configured samba servers inherited this configuration naturally. However when I test the samba performance of my latest configured Dell PowerEdge Data server, the result is astonishing. Its throughput is only around~12 to 15 MB/s. Even a cheap latest NAS can have samba performance approach 80 to 90MB/s easily on a gigabit network. I noticed there should be something wrong in samba config on the Dell Server. After a quick search, I have found the read and write buffer setting of socket options in smb.conf :SO_SNDBUF=8192 SO_RCVBUF=8192 should be already obsoleted on Linux 2.6 kernel or later. After remove the send and write buffer setting in the socket options, the samba performance bumped to over 111MB/s at peak. I am quite surprised by the fact that the send and receive buffer settings can hinder the performance in that magnitude.

BTW, I think I can use this option to SLOW DOWN the samba throughput of modern server if the samba consumed too much resources.