From owner-freebsd-current@FreeBSD.ORG Wed May 26 19:51:40 2004 Return-Path: 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 490F516A4CE for ; Wed, 26 May 2004 19:51:40 -0700 (PDT) Received: from mail.dt.e-technik.uni-dortmund.de (mail.dt.e-technik.Uni-Dortmund.DE [129.217.163.1]) by mx1.FreeBSD.org (Postfix) with ESMTP id B8C6443D41 for ; Wed, 26 May 2004 19:51:39 -0700 (PDT) (envelope-from ma@dt.e-technik.uni-dortmund.de) Received: from m2a2.dyndns.org (krusty.dt.e-technik.uni-dortmund.de [129.217.163.1])9392F2D7D6; Thu, 27 May 2004 04:51:14 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by merlin.emma.line.org (Postfix) with ESMTP id DF03CBEC07; Thu, 27 May 2004 04:51:12 +0200 (CEST) Received: from merlin.emma.line.org ([127.0.0.1]) by localhost (m2a2.dyndns.org [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 06828-05-2; Thu, 27 May 2004 04:51:10 +0200 (CEST) Received: by merlin.emma.line.org (Postfix, from userid 500) id 07C52BEC05; Thu, 27 May 2004 04:51:09 +0200 (CEST) To: Brad Knowles In-Reply-To: (Brad Knowles's message of "Wed, 26 May 2004 22:28:41 +0200") References: <40B4ECC8.50808@fer.hr> From: Matthias Andree Date: Thu, 27 May 2004 04:51:09 +0200 Message-ID: User-Agent: Gnus/5.110003 (No Gnus v0.3) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Virus-Scanned: by amavisd-new at m2a2.dyndns.org cc: current@freebsd.org Subject: softupdates and caches/tagged queuein (was: Softupdates a mount option?) X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 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: Thu, 27 May 2004 02:51:40 -0000 Brad Knowles writes: > At 9:15 PM +0200 2004/05/26, Ivan Voras wrote: > >> This has been really nagging me for a long time: Why aren't softupdates >> made a mount option (like 'sync' and 'async')? Do I remember correctly >> that it is done so in NetBSD (where it's called softdeps), so it's doable? > > You need to read the documentation from Kirk. In short, this > was intentional -- the goal is that this feature will be turned on > permanently, at which point there's no sense in having yet another > useless mount option laying around. IIRC, the license is written such > that you are not *allowed* to make this a mount option, for this reason. > > Kirk is really serious about this. You should read the Ganger & > Platt paper, as well as the other documentation written by Kirk on this > subject. Speaking of which, does this fine file system (softupdates) know how to use - ordered tags (SCSI) - flush cache commands (ATA) (or other barrier approaches) to enforce write order where necessary? I'm wondering a bit for one of my SCSI drive defaults to (control page) queue algorithm modifier = 1 and (caching page) WCE = 1 which means it can reorder at will unless someone uses ordered tags or the do-this-now tag (I forgot the name) - and this discussion is a bit "hot" in the Linux lists ATM. -- Matthias Andree Encrypted mail welcome: my GnuPG key ID is 0x052E7D95