[Samba] Samba process throttled back?

[Lang, Rich]

The clients may have undergone a change (Windows is always being patched), but the configuration of the server was not changed regarding oplocks.  No requests are being denied, since that situation would show up in the log file.



-----Original Message-----
From: Jeremy Allison [mailto:jra at samba.org]
Sent: Monday, June 20, 2011 3:49 PM
To: Lang, Rich
Cc: samba at lists.samba.org
Subject: Re: [Samba] Samba process throttled back?



On Fri, Jun 17, 2011 at 09:39:16AM -0400, Lang, Rich wrote:

> Hello,

>

> We are running Samba 3.0.33 on a 2-node Linux cluster running RedHat 5.6 ES.  Its primary application is to serve out a single network drive to support our business (out 350GB in size).  For several years, this solution has been running flawlessly.  File access was almost as fast as a local disk, so putting files on the server was never a problem.  Our clients are running mostly Windows XP Pro.  We have a few Windows 7 clients.

>

> Almost a year ago, that changed.  Applications written in VB 6.0 that read files from the server started showing *significant* performance problems.  What used to take seconds now takes more than a minute to finish.  Moving the file to a local disk brought the speed back up to where it should be.  Moving the file to a Windows 2003 or 2008 server also provided good throughput.  All clients experience this same problem.

>

> I ran "strace -f" against the smbd process that is assigned to my desktop and then ran the VB application to see what the daemon was up to.  I discovered that it went through a process of opening the file several times and reading data from it, using progressively smaller buffer sizes until is settled on using a buffer size of 1, which it used for the remainder of the file I/O session.



This *seems* like clients not using oplocks, when previously they were. Has anything changed in the server system that might be denying oplock requests ?



Jeremy.

Richard G. Lang
Sr. Software Engineer
LangR at specsensors.com<mailto:LangR at specsensors.com>
(330) 659-3312