From owner-freebsd-stable Fri Sep 14 5:27:32 2001 Delivered-To: freebsd-stable@freebsd.org Received: from madeline.boneyard.lawrence.ks.us (madeline.boneyard.lawrence.ks.us [24.124.26.25]) by hub.freebsd.org (Postfix) with ESMTP id 3A11E37B407 for ; Fri, 14 Sep 2001 05:27:28 -0700 (PDT) Received: from madeline.boneyard.lawrence.ks.us (madeline.boneyard.lawrence.ks.us [24.124.26.25]) by madeline.boneyard.lawrence.ks.us (8.11.1/8.11.1) with ESMTP id f8ECROO05423; Fri, 14 Sep 2001 07:27:25 -0500 (CDT) (envelope-from bsd-stable@boneyard.lawrence.ks.us) Date: Fri, 14 Sep 2001 07:27:24 -0500 (CDT) From: "Stephen D. Spencer" To: ian j hart Cc: "stable@FreeBSD.ORG" Subject: Re: kernel oplocks In-Reply-To: <3B9FE8D6.40EBB7E@ntlworld.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG On Wed, 12 Sep 2001, ian j hart wrote: > Date: Wed, 12 Sep 2001 23:59:34 +0100 > From: ian j hart > To: "stable@FreeBSD.ORG" > Subject: kernel oplocks > > Samba now comes configured with kernel oplocks enabled by > default, implying this is part of the kernel. Can someone > confirm the status of this. ie is it established, or is it > a new feature. I wouldn't mind knowing where the source is. > A quick search revealed nothing. > I just went through this over the last couple weeks. Currently, the only systems that currently support kernel oplocks are IRIX and Linux 2.4.x. Without kernel oplocks, samba has support for generic user-land oplock support. This support is broken... something about spinning fcntl locks if I remember correctly. At any rate, explicitly turning oplocks off will do away with the error messages and (if you haven't seen them yet) the eventual freezing up of your smbd process. From my research, it appears that oplocks are a performance feature that alots file/record(?) locking capabilities to the client for as long as that client is the only system accessing the file in question. (does away with the latency of going over the network to do file/record(?) locking. I'm not an expert on this subject, so I would send you elsewhere for a definitive description on what oplocks are. The Using Samba O'Reilley book is included with the samba docs and includes a description and some diagrams involving how oplocks work and what they are for) If someone else comes along and accesses the file, the server is supposed to force the client to give up its oplock and go back to the server for locking operations. At any rate, there have been a number of commits to oplock.c since the release of 2.2.1a in July. I'm waiting for these updates to either settle or for 2.2.2 to come out before re-enabling oplocks. In the mean time, our file server being the big, beefy box that it is, is having no difficulty keeping up with the load sans oplocks. Stephen Spencer | | "Mutton yesterday, mutton today, and blimey, | if it don't look like mutton again tomarrer" | -Bert To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message