From owner-freebsd-fs@FreeBSD.ORG Tue Feb 13 17:16:40 2007 Return-Path: X-Original-To: freebsd-fs@FreeBSD.ORG Delivered-To: freebsd-fs@FreeBSD.ORG Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id D075C16A407 for ; Tue, 13 Feb 2007 17:16:39 +0000 (UTC) (envelope-from olli@lurza.secnetix.de) Received: from lurza.secnetix.de (lurza.secnetix.de [83.120.8.8]) by mx1.freebsd.org (Postfix) with ESMTP id 45F4C13C4BB for ; Tue, 13 Feb 2007 17:16:38 +0000 (UTC) (envelope-from olli@lurza.secnetix.de) Received: from lurza.secnetix.de (bmtuhk@localhost [127.0.0.1]) by lurza.secnetix.de (8.13.4/8.13.4) with ESMTP id l1DHGVxp000720; Tue, 13 Feb 2007 18:16:37 +0100 (CET) (envelope-from oliver.fromme@secnetix.de) Received: (from olli@localhost) by lurza.secnetix.de (8.13.4/8.13.1/Submit) id l1DHGVsN000719; Tue, 13 Feb 2007 18:16:31 +0100 (CET) (envelope-from olli) Date: Tue, 13 Feb 2007 18:16:31 +0100 (CET) Message-Id: <200702131716.l1DHGVsN000719@lurza.secnetix.de> From: Oliver Fromme To: freebsd-fs@FreeBSD.ORG, chris@sigd.net In-Reply-To: <6FC9F9894A9F8C49A722CF9F2132FC2204C9DAB6@ms05.mailstreet2003.net> X-Newsgroups: list.freebsd-fs User-Agent: tin/1.8.2-20060425 ("Shillay") (UNIX) (FreeBSD/4.11-STABLE (i386)) MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.1.2 (lurza.secnetix.de [127.0.0.1]); Tue, 13 Feb 2007 18:16:37 +0100 (CET) Cc: Subject: Re: UFS2 with SAN X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: freebsd-fs@FreeBSD.ORG, chris@sigd.net List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 13 Feb 2007 17:16:40 -0000 Chris Haulmark wrote: > If your responses on this SAN thread would not be productive, please > stay out. I am not interested to hear lectures about what is impossible. But maybe others are interested to hear that information. > I asked about if anyone has tried to use UFS2 with only one node to > have write/read only while the rest would be read only. And you already got the answer, see Eric's mail. He wrote: | This will result it the read/write system seeing the data ok, | and the rest getting corrupt data without knowing it, and | probably crashing. UFS2 is not cluster aware. Eric is right. For UFS to be cluster-aware, it would need to implement a cache-coherency protocol, so every node knows what data is up-to-date and what data is stale. UFS doesn't do that at all because it was designed as a local-only file system. The only way it would work is to mount _all_ of the nodes read-only. When you need to update data, you must remount the file system read-write on one node _and_ unmount it on all other nodes. I don't think that you want to do that, though. Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing b. M. Handelsregister: Registergericht Muenchen, HRA 74606, Geschäftsfuehrung: secnetix Verwaltungsgesellsch. mbH, Handelsregister: Registergericht Mün- chen, HRB 125758, Geschäftsführer: Maik Bachmann, Olaf Erb, Ralf Gebhart Any opinions expressed in this message are personal to the author and may not necessarily reflect the opinions of secnetix GmbH & Co KG in any way. FreeBSD-Dienstleistungen, -Produkte und mehr: http://www.secnetix.de/bsd "UNIX was not designed to stop you from doing stupid things, because that would also stop you from doing clever things." -- Doug Gwyn