Hello There,
After having googled the whole internet for days I decided to go public
with this issue.
The result of my google queries so far is that there are plenty of
others with the very same problem I have and noone posted a reasonable
answer to this:
Using Samba 3 with XP gets bad performance. I tested this on Tru64 5.1b
and FreeBSD 5.3 with the very same symptoms.
The throughput bw XP and Samba goes up and down. It starts transfering
with a reasonable speed and after having transfered around 16 megs it
slows down.
I tried many configuration options regarding locking, tcp settings, xmit
size and every combination that could make any sense for me.
Then I gave up with this configuration mess as I could lower the
performnce easily, but the performance jittering was the same.
Now a few notes before I continue: I tested the FreeBSD server on the
loopback interface and the file write speed was around 43 Megs that is
close to the disks maximum. I also tested the XP machine with a Windows
server and the write performnce was around 10 Megs on a 100Mbit link. In
addition to that the FreeBSD machine is at my home and the Tru64 and the
Windows server are where I work. I'm pretty sure that this is not a
network issue.
After spending a lot of time with investigation I decided to go deeper
in this issue. I installed ethereal to capture the traffic and compare
the results bw XP-Windows and XP-Tru64. The test was to copy 50Meg file
to both servers and capture the packets. To my surprise the conversation
was quite different.
XP-Windows (excerpt):
- nt create and x
- trans2: query file info internal
- set file info
- tcp data stream...
XP-Samba (excerpt):
- nt create and x
- trans2: query file info internal
- (query file info + write and x request) many times, incresing offset,
one byte length
- tcp data stream....
In case of XP-Samba, the last two steps are repeated many times.
Large part of the effective bandwith is filled with query file info and
1 byte writes.
The packet data can be downloaded from these links:
http://dbeck.beckground.hu/download/xp-samba.bz2
http://dbeck.beckground.hu/download/xp-win.bz2
I also made a screenshot of a bandwith monitor to show what I mean by
performance jittering:
http://dbeck.beckground.hu/download/samba-performance-write.PNG
http://dbeck.beckground.hu/download/samba-performance-read.PNG
Please note that the original packet log for the 50 Meg file was very
large, so I kept only the interesting parts.
Last, could anyone there, Samba and SMB wizards help me, how to solve
this performance issue?
Thank you in advance,
David.
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