From owner-freebsd-current@FreeBSD.ORG Fri May 27 09:25:53 2005 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id DB82816A41C for ; Fri, 27 May 2005 09:25:53 +0000 (GMT) (envelope-from PeterJeremy@optushome.com.au) Received: from mail03.syd.optusnet.com.au (mail03.syd.optusnet.com.au [211.29.132.184]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5337343D4C for ; Fri, 27 May 2005 09:25:53 +0000 (GMT) (envelope-from PeterJeremy@optushome.com.au) Received: from cirb503493.alcatel.com.au (c211-30-75-229.belrs2.nsw.optusnet.com.au [211.30.75.229]) by mail03.syd.optusnet.com.au (8.12.11/8.12.11) with ESMTP id j4R9Plqq032226 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Fri, 27 May 2005 19:25:50 +1000 Received: from cirb503493.alcatel.com.au (localhost.alcatel.com.au [127.0.0.1]) by cirb503493.alcatel.com.au (8.12.10/8.12.10) with ESMTP id j4R9PlRx018840; Fri, 27 May 2005 19:25:47 +1000 (EST) (envelope-from pjeremy@cirb503493.alcatel.com.au) Received: (from pjeremy@localhost) by cirb503493.alcatel.com.au (8.12.10/8.12.9/Submit) id j4R9Pi4l018839; Fri, 27 May 2005 19:25:44 +1000 (EST) (envelope-from pjeremy) Date: Fri, 27 May 2005 19:25:44 +1000 From: Peter Jeremy To: Scott Long Message-ID: <20050527092544.GB18696@cirb503493.alcatel.com.au> References: <42960ACB.7090801@cs.tu-berlin.de> <42960CFE.4060307@centtech.com> <42960F8F.2050109@samsco.org> <42961195.30608@centtech.com> <429613FB.80100@samsco.org> <42968AD4.3020603@centtech.com> <4296997C.9030700@samsco.org> <20050526235852.M54386@lexi.siliconlandmark.com> <42969C1B.5010301@samsco.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <42969C1B.5010301@samsco.org> User-Agent: Mutt/1.4.2i Cc: FreeBSD Current Subject: Re: Disable read/write caching to disk? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 27 May 2005 09:25:54 -0000 On Thu, 2005-May-26 22:03:39 -0600, Scott Long wrote: >A few people have suggested modifying UFS to fill this role. It probably >is just as much work as porting GFS, if not more, since UFS/FFS is >closely tied to the buffer cache and block layers on BSD, and divorcing >probably would be quite difficult. It's probably worth noting that (AFAIK) none of the commercial vendors have managed to build a multi-master shared UFS filesystem. This suggests that the effort is considerable. Solaris clustering routes all I/O to a shared filesystem to a single 'master' node, which is responsible for all physical I/O to the disk. This would significantly simplify cache coherency management. Tru64 clustering only really supports AdvFS. Limited UFS support was added in 5.1B - all the cluster members can mount a UFS filesystem but only one can have a R/W mount and all I/O is routed through a single "master" node. -- Peter Jeremy