[Samba] Transfer speed

Steve French smfrench at gmail.com
Fri Apr 13 15:47:34 MDT 2012

On 03:06:34 wrote Stan Hoeppner:
> On 4/10/2012 9:36 AM, Volker Lendecke wrote:
> > On Tue, Apr 10, 2012 at 08:55:14AM -0500, Chris Weiss wrote:
> >> On Tue, Apr 10, 2012 at 8:53 AM, Volker Lendecke
> >>
> >> <Volker.Lendecke at sernet.de> wrote:
> >>> On Tue, Apr 10, 2012 at 08:26:48AM -0500, Chris Weiss wrote:
> >>>> that's dramatic!  what needs done (from a user POV) to get this
> >>>> backported into Stable distro kernels?  suggestions?
> >>>
> >>> Wait until the next major releases pick it up.
> >>
> >> that's a really crappy option.  in certain cases that
> >> could be 4 years from now.
> >
> > Well, if you are an important enough RH customer you might
> > be able to apply pressure. But that's a LOT of money
> > probably. Same for SuSE. Debian will likely be very
> > resistant against that kind of bribery^Wincentive.
> Debian already has 3.2.6 available in the stable repo:
> $ aptitude search linux-image
> ...
> i   linux-image-3.2.6           - Linux kernel, version 3.2.6
> ...

My Fedora is running 3.3 and performance screams
with reads and writes over cifs, especially to Samba.

At least SuSE and RHEL6.2 appear to have upgraded
their kernel far enough to get the really fast
writes over cifs.  Jeff Layton did a good job on these
performance patches.   Hard to complain about 95%
network utilization (and it will get even better when
the SMB2 and SMB2.1 support is merged).

You will be even happier with 3.4 kernel on the client
because then you can get even more parallelism
(assuming you have a big set of disks to distribute
work across on your server) when you set much larger values for
"max mux" in the server's smb.conf you will be able
to get up to 32768 requests in parallel queued to Samba.
With today's networks and Samba the default for servers
(of 50) is way too low - and with 3.4 kernel cifs client
we will be able to send even more requests in parallel
if the server indicates it can support it (more than 50
maximum multiplex requests).

Note that Linux cifs kernel client always supported great parallelism
and would easily use most of the network bandwidth if multiple
processes were doing i/o against multiple files on the same
mount - but with 3.0 (for sequential write like file copies)
and later kernels for reads - cifs is VERY fast now.

Prior to 3.0 kernel for fast file copies from Windows
or Samba servers you can use smbclient (user space tool)
which due to good work by Volker has had nice performance
for sequential read/wirte for a few years.



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