At startup the client and server negotiate a
which limits the size of nearly all SMB commands. You can set the
maximum size that Samba will negotiate using the
max xmit option
smb.conf. Note that this is the maximum size of SMB requests that
Samba will accept, but not the maximum size that the client will accept.
The client maximum receive size is sent to Samba by the client, and Samba
honors this limit.
It defaults to 65536 bytes (the maximum), but it is possible that some
clients may perform better with a smaller transmit unit. Trying values
of less than 2048 is likely to cause severe problems.
In most cases the default is the best option.