Bug 10856 - Samba upload speed over WiFi drops after some seconds
Summary: Samba upload speed over WiFi drops after some seconds
Alias: None
Product: Samba 4.1 and newer
Classification: Unclassified
Component: libsmbclient (show other bugs)
Version: 4.2.0
Hardware: x64 Linux
: P5 major (vote)
Target Milestone: ---
Assignee: Samba QA Contact
QA Contact: Samba QA Contact
Depends on:
Reported: 2014-10-06 14:00 UTC by Ettore Atalan
Modified: 2014-11-23 01:40 UTC (History)
2 users (show)

See Also:


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Description Ettore Atalan 2014-10-06 14:00:49 UTC

I'm using Samba to up- and download files on/from my NAS.

Uploading files on my NAS using SMB is quite depressing. The upload speed begins at around 4.5 MB/s (like on Windows 7 all the time) and then collapses to around 0.6 MB/s after some seconds (10 – 20 secs). The iwlwifi driver "works perfectly" (see URL), but I don't find any Samba error message in the syslog, but something is definitely wrong.

Best Regards,
Ettore Atalan
Comment 1 Jeremy Allison 2014-11-06 20:34:38 UTC
Try doing an ftp transfer without Samba being involved over the same wifi connection. That will give you more data on how much SMB is affecting the problem.
Comment 2 Ettore Atalan 2014-11-06 23:53:15 UTC
FTP works without any problems as good as SMB on Windows.
Comment 3 Jeremy Allison 2014-11-07 00:43:44 UTC
So SMB is very sensitive to packet loss, with the default algorithms on a Linux server. What is your NAS make of ?
Comment 4 Ettore Atalan 2014-11-07 12:53:23 UTC
My NAS is a QNAP TS-110 with latest firmware version 4.1.1 running Samba version 3.6.23.
Comment 5 Jeremy Allison 2014-11-07 16:57:18 UTC
OK, this almost certainly isn't a Samba problem, but a Linux TCP issue dealing with a lossy network.

Check this out:


and I'd try:

echo "westwood" > /proc/sys/net/ipv4/tcp_congestion_control
Comment 6 Ettore Atalan 2014-11-07 17:51:00 UTC
Thanks for the link.

The "cubic" algorithm is selected currently.
Comment 7 Ettore Atalan 2014-11-08 14:13:56 UTC
The upload speed is going up and down continuously (from 100 kB/s – 3000 kB/s)  with the "westwood" algorithm. Not really an improvement to the 600 kB/s before.
Comment 8 Ettore Atalan 2014-11-13 13:03:27 UTC
No idea what's going wrong?
Comment 9 Ettore Atalan 2014-11-23 01:40:21 UTC
Is it a TCP bug?