[Samba] Client link utilization

Jeremy Allison jra at samba.org
Tue Feb 9 09:19:37 MST 2010

On Tue, Feb 09, 2010 at 10:25:44AM -0500, Lennart Sorensen wrote:
> On Tue, Feb 09, 2010 at 01:19:40AM +0100, Bostjan Skufca wrote:
> > Then I am greedier (if I also strive for 11MB/s:) Thanks for reminding
> > me though.
> > 
> > Can/Did someone push it over 10MB/s (or 100MB/s with 1Gbps ethernet))?
> > 
> > 
> > To Jeremy or someone who is involved in samba as a developer: do any
> > particular kernel options influence performance of smbclient, that you
> > know of? Compile time options? Compiler version?
> Well I just checked what settings my NFS mount that works great is using.  it uses:
> rw,relatime,vers=3,rsize=1048576,wsize=1048576,namlen=255,hard,proto=tcp,timeo=600,
> retrans=2,sec=sys,mountvers=3,mountproto=udp
> Now I tried different rsize values with cifs as well, but that doesn't
> seem to help (at least 64k made no improvement.  Going down to 4k made
> it slower).
> Looking at it carefully, it turns out trying to set it over 16k gets
> ignored.  Changing the option CIFSMaxBufSize on the cifs module to 130048,
> does allow using rsize up to that value, and the speed goes up to 8.3MB/s
> from 7.5MB/s.  So it seems larger rsize makes it better.  Given nfs uses
> 8 times larger yet and gets great speed may be a clue too.

There are two issues here. One is the problem with the
Linux CIFSFS which you're talking about. FYI. Samba is
able to cope with single request read/write sizes up to
16MB from a UNIX extension client (smbclient can do this)
so you might want to talk to Steve French to learn how
to turn this on.

The second issue is the one with Windows clients. As
the redirectors are completely different, with completely
different requests and semantics I'd rather not get the
two confused in this thread. Please split out another
mailing list thread for the CIFSFS client speed issue,
so we have them clearly separated.


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