[Samba] Odd, slow Windows XP client download behavior

Kimon Gazis kimon at gazis.de
Sun Jan 13 08:48:48 GMT 2008

I have the very same situation here with Samba 3.0.28 (amd64 debian etch
testing) and my two XP client machines (32 Bit and x64 Prof. Edition
both SP2). FTP speeds are at reasonable levels in both directions and
SMB uploads to the server as well whereas SMB downloads onto the client
machines are extremely slow (around 300KB/s).

I can also confirm the strange effect described by Chris with rising
downstream speeds when simultaneously uploading something. In my case I
had a speedtest using "netio" pushing datagrams onto the samba server
eg. completely smb unrelated! I checked the other direction having
simultaneous downloads and yielded that effect as well.

The problem is independent of the client's network interface as I tried
both the WLAN 54 adaptor and the Realtek GBit NIC on XP client side.
With contrast to Chris I had no differences when playing with samba
parameters like oplock (also no difference when done on the windows client).

I booted one client machine to debian etch (stable) and ran tests using
NFS and FTP yielding full GBit LAN speeds.

I tested Windows Server 2003 clients inside VMWares running on the XP
clients and on the samba server itself. No performance issues there.
Downloading files from the windows VM running on the samba server (!)
onto the XP clients works like a charm as well. (So does the other way
round!). SMB communication between the two XP machines works anyway.

I finally smbmounted shares of the XP clients on the samba server and
copied files onto them at reasonable speeds (around 40MB/s). Copying
(downloading) onto the server was around 20MB/s.

I have no other samba problems. Everything else works fine: browsing,
printing, WINS etc.

In my opinion there is no connection to a Hardwareproblem. Instead we
experience some behaviour of the XP client machines that cause this. It
seems to be SMB/CIFS related but I think we need to further investigate
to get more hard data. Maybe capture some SMB packets using wireshark
while doing the downloads and compare them ?!? However I am no
networking guy so I would need some guidance on what to do exactly.


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