If
max
xmit is commonly called the write size, you'd expect
read
size to be the maximum amount of data that Samba would want to read from the client via the network. Actually, it's not. In fact, it's an option to trigger
write ahead. This means that if Samba gets behind reading from the disk and writing to the network (or vice versa) by the specified amount, it will start overlapping network writes with disk reads (or vice versa).
The read size doesn't have a big performance effect on Unix, unless you set its value quite small. At that point, it causes a detectable slowdown. For this reason, it defaults to 2048 and can't be set lower than 1024.
