use sendfile (S) If this parameter is yes, and Samba was built with the --with-sendfile-support option, and the underlying operating system supports sendfile system call, then some SMB read calls (mainly ReadAndX and ReadRaw) will use the more efficient sendfile system call for files that are exclusively oplocked. This may make more efficient use of the system CPU's and cause Samba to be faster. This is off by default as it's effects are unknown as yet. Default: use sendfile = no