[Samba] Samba process throttled back?

Lang, Rich LangR at specsensors.com
Thu Jun 23 14:32:42 MDT 2011

Thanks to all who responded.

This shouldn't be anything to do with oplocks, although I understand their nature and how they can destroy performance.  The file I analyze is being accessed by no one but me - guaranteed.  We're a small company and I know that to be true.

I reverted the secondary cluster member from Samba 3.5.9 back to 3.0.33 and, voila' - the slow performance returned.  No one else in the company even knows that this share exists, so this performance degradation isn't because someone else is breaking my oplock.

I ran a wireshark analysis on the net during a "fast" file analysis (under Samba 3.5.9) and a "slow" analysis (under Samba 3.0.33).  The SMB protocol shows that the client is the one that is ratcheting-down the file access to where single bytes are being retrieved from the server.  Under Samba 3.5.9, the client is retrieving data using 4096-byte blocks.

This may have happened due to a Microsoft update to the client at that point in time and 3.0.33 isn't responding correctly somehow.  I haven't found the real reason - I just know that 3.5.9 appears to work when 3.0.33 doesn't.  However, 3.0.33 *does* work on the active cluster member.


-----Original Message-----
From: Jeremy Allison [mailto:jra at samba.org] 
Sent: Thursday, June 23, 2011 12:09 PM
To: Volker Lendecke
Cc: Lang, Rich; samba at lists.samba.org
Subject: Re: [Samba] Samba process throttled back?

On Thu, Jun 23, 2011 at 05:31:14PM +0200, Volker Lendecke wrote:
> Hi!
> I'd rather assume an oplock break. As long as you're alone
> on the file, it's fast. Once somebody else opens (or even
> just takes a look at) the file, it's slow. This can be
> confirmed with a network trace.

Yes, this is what screamed out to me. It has to be oplock
related IMHO.


More information about the samba mailing list