From owner-freebsd-stable@FreeBSD.ORG Mon Mar 29 21:55:05 2010 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id BABAF1065670 for ; Mon, 29 Mar 2010 21:55:05 +0000 (UTC) (envelope-from rmacklem@uoguelph.ca) Received: from esa-jnhn.mail.uoguelph.ca (esa-jnhn.mail.uoguelph.ca [131.104.91.44]) by mx1.freebsd.org (Postfix) with ESMTP id 45E6D8FC1C for ; Mon, 29 Mar 2010 21:55:04 +0000 (UTC) X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvsEABu+sEuDaFvK/2dsb2JhbACbJ3G/f4UBBA X-IronPort-AV: E=Sophos;i="4.51,330,1267419600"; d="scan'208";a="70401664" Received: from fraser.cs.uoguelph.ca ([131.104.91.202]) by esa-jnhn-pri.mail.uoguelph.ca with ESMTP; 29 Mar 2010 17:55:04 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by fraser.cs.uoguelph.ca (Postfix) with ESMTP id 4D520109C2E3; Mon, 29 Mar 2010 17:55:04 -0400 (EDT) X-Virus-Scanned: amavisd-new at fraser.cs.uoguelph.ca Received: from fraser.cs.uoguelph.ca ([127.0.0.1]) by localhost (fraser.cs.uoguelph.ca [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id KV0n4wYpp0UJ; Mon, 29 Mar 2010 17:55:03 -0400 (EDT) Received: from muncher.cs.uoguelph.ca (muncher.cs.uoguelph.ca [131.104.91.102]) by fraser.cs.uoguelph.ca (Postfix) with ESMTP id E167D109C2E1; Mon, 29 Mar 2010 17:55:03 -0400 (EDT) Received: from localhost (rmacklem@localhost) by muncher.cs.uoguelph.ca (8.11.7p3+Sun/8.11.6) with ESMTP id o2TM8Jm15195; Mon, 29 Mar 2010 18:08:19 -0400 (EDT) X-Authentication-Warning: muncher.cs.uoguelph.ca: rmacklem owned process doing -bs Date: Mon, 29 Mar 2010 18:08:19 -0400 (EDT) From: Rick Macklem X-X-Sender: rmacklem@muncher.cs.uoguelph.ca To: Jeremy Chadwick In-Reply-To: <20100329165647.GA3796@icarus.home.lan> Message-ID: References: <20100329165647.GA3796@icarus.home.lan> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-stable@freebsd.org Subject: Re: Strange NFS-related messages (related to lockd/statd) X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 29 Mar 2010 21:55:05 -0000 On Mon, 29 Mar 2010, Jeremy Chadwick wrote: > > I can't find a definition of what the acronyms NLM and NSM stand for, > nor does Googling the error messages return relevant results (except one > FreeBSD committer reporting similar, but nobody replied). I don't know > the implications of these messages. > NLM - Network Lock Manager NSM - Network Status Monitor (I think?) These two protocols (separate from NFS) were what Sun implemented in the 1980s to provide locking on NFS mount points. Imho, these protocols were poorly designed: - The NLM allows blocking locks at the server, which can cause assorted nasty issues when the client crashes or gets network partitioned. - It also depended on the NSM to decide when machines were up/down and the NSM protocol basically did this in a rather poor way. A big part of NFSv4 was the integration of locking, in order to avoid use of the above. (As you might have guessed, lockd and statd implement the above two protocols. rick