[Samba] linux 2 linux transfer very slow

Jeff Layton jlayton at samba.org
Mon Oct 26 05:07:27 MDT 2009

On Mon, 26 Oct 2009 00:24:48 +0100
"Jean-Yves F. Barbier" <12ukwn at gmail.com> wrote:

> Debian sid V. 3.4.2-1
> Debian lenny
> =====================
> Hi list,
> Sometimes ago I noticed a samba slowing down but as I don't use it 
> very much it was not a PB (NO conf changes.)
> Today I made this test on CLI:
> mount -t cifs //svr/myshare /mnt/ -o username=myuser,password=mypw,ro
> then: 
> cp /mnt/films/20090911_0025_footage.avi . (this one's 2GB)
> The speed (measured w/ iptraf) is terribly slow (~750KB/s), so I made 
> another test: ftp using filezilla: ~7500KB/s (!)
> There's nothing special in my conf file, and I've got a line as doc say:
> I really don't understand why there's so much difference between samba & ftp
> mostly because formerly (well, may be a year ago) there was only a very small
> gap between these speeds.

This probably has little to do with samba and more to do with the fact
that writes with Linux CIFS are essentially synchronous within the
context of a single thread.

That said, your SO_RCVBUF size seems very small. You probably at least
need to make it large enough to hold a few writes before closing the
window. The folks who work on the samba server might be able to offer
better guidance as to a size.

Jeff Layton <jlayton at samba.org>

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