[Samba] single stream performance issue, Win2K, WinXP, Samba 3.2.5-4lenny7 (Debian Lenny)

Stan Hoeppner stan at hardwarefreak.com
Sun Jan 24 12:13:02 MST 2010

Volker Lendecke put forth on 1/24/2010 5:04 AM:
> On Sat, Jan 23, 2010 at 02:11:04PM -0600, Stan Hoeppner wrote:
>> The 11MB/s was a different test, which I clearly stated.
>> It consisted of two concurrent single stream file copies
>> _from_ the Samba server _to_ a Win2K workstation using
>> standard Windows Explorer as the file copy program.  This
>> test saturated one leg of the 100FDX ethernet connection
>> at ~11.5MB/s.
> Just a quick hint: Single stream performance really heavily
> depends on the concrete client behaviour. smbclient from 3.2
> and higher should give you good performance. And watch out
> which program on the Windows client you use to do the copy.
> xcopy, robocopy and the Windows explorer on some OS version
> give dramatically different results. The difference comes
> from overlapping requests or their absence.

I just tested xcopy with the previously mentioned 600MB+ file between my Win2K
Pro workstation and the WinXP workstation, single stream, both directions.  I
also did the same xcopy tests between the Win2K Pro workstation and the Samba
server.  The b/w results are identical to the previous Windows Explorer file
copy tests, 8MB/s up/down to Samba, and a little over 10MB/s up/down to the
WinXP machine.

Are overlapping requests the cause of the single stream performance issue here?
 If so, are overlapping requests something that is negotiated in the SMB
protocol between the hosts or is it statically configured, or something compiled
into the client code?  I.e. if overlapping requests is the issue, why do the two
Windows machines seem to do it correctly between themselves, but the
Windows/Samba combination does not?

Is there something I can manually configure on Win2K Pro to overlap requests
to/from Samba?

Thanks for the assistance, insight, and education.


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