network extremely slow

Neil Hoggarth neil.hoggarth at
Thu Aug 24 10:12:58 GMT 2000

On Wed, 23 Aug 2000, Peter Pilsl wrote:

> I run a samba-server with 15nt-clients on a 100MBit-Switch.  Now I
> faced extremely poor performance and really have no idea why. I even
> dont know if it can be a samba-problem.

Hi Peter,

It probably isn't a Samba problem, given that you comment that NT-NT
transfers are even worse. The standard test to perform when confronted
with this sort uncertainty is to measure the transfer speed of a
different network protocol which also does bulk data transfer, such as
FTP. If you can FTP between two machines very much faster then you can
copy over SMB then it is possible that you have a Samba/SMB
configuration problem. If FTP is also very slow then you probably have a
more fundamental TCP/IP problem or Ethernet problem.

This kind of thing is seems to often be most often caused by incorrect
setting of duplex on Ethernet connections. Are the workstations
operating at full-duplex or half-duplex? If all the devices on the
network are 100BASE-T then auto-negotiation ought to work correctly. Did
you "force" anything to be full-duplex?

Check that your "100Mbit-switch" really is a switch! I've seen a lot of
manufacturers recently selling products with descriptions similar to
"10/100 switched hub", which I regard as rather misleading. These are
often what I would actually describe as a dual speed hub: you basically
get a 10BASE-T hub, a 100BASE-T hub and a two port switch joining the
10BASE-T and the 100BASE-T segments, all in the same box. Traffic
between two 100BASE-T devices attached to such a device is *not*
switched, and it is *not* appropriate to use a network cards in
full-duplex mode.

Neil Hoggarth                                 Departmental Computer Officer
<neil.hoggarth at>                   Laboratory of Physiology                  University of Oxford, UK

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