Samba performance problem over a radio link.

[Marco Bizzarri]

Hi all.

We have a performance problem over a 2 Mbits radio link.

The configuration is as follows: we have a RH Linux 6.1 (double PIII
processor, 100 mbit ethernet, raid 5), acting as a server for a network
of Windows 95, 98 and NT. On the local network I can achieve up to 40
mbits transferring large files from the server to a windows 98 machine.

This network is connected through a 2 mbits radio link to another 10
mbits network. There we have an NT workstation, an 95 and a 98 machine.

A samba read performed by the 95 or the 98 machine provides
approximately 70KB/sec. An ftp get from the same server 100KB/sec. The
same read operation, performed by the WinNT machine, achieves 100KB/sec.
Reading from an NT server on the 100MBit network provides 160KB/sec,
which is near the maximum performance.

I read through the on-line O'Reilly book about performance, and I
experimented a lot using mtuspeed410. However, I was unable to produce
any meaningful improvement. We tryied from 296 to 1500 as MaxMTU value,
and from 2x to 6x RWin. The best performance were obtained by 1152 MTU
and Rwin x4

Now I understand performance can greatly vary according to the settings
in the socket options, however, since experimenting can be a problem for
us (the network is in another town, and I have to make tests onto
windows machines also), I would like to know if there is some
"reasonable" way to find the parameters to be set, both on the windows
machine and on the samba server. I understand trial and error is an
option, but I would like to know if there is anything else which could
be used to narrow all the possible options.

Please feel free to answer me directly.

Bye
Marco Bizzarri