From owner-freebsd-fs Tue Jan 21 1: 2:18 2003 Delivered-To: freebsd-fs@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 4F72F37B401 for ; Tue, 21 Jan 2003 01:02:17 -0800 (PST) Received: from thebsh.namesys.com (thebsh.namesys.com [212.16.7.65]) by mx1.FreeBSD.org (Postfix) with SMTP id 54AC143E4A for ; Tue, 21 Jan 2003 01:02:15 -0800 (PST) (envelope-from Nikita@Namesys.COM) Received: (qmail 20450 invoked from network); 21 Jan 2003 09:02:14 -0000 Received: from laputa.namesys.com.7.16.212.in-addr.arpa (HELO laputa.namesys.com) (212.16.7.124) by thebsh.namesys.com with SMTP; 21 Jan 2003 09:02:14 -0000 Received: by laputa.namesys.com (Postfix on SuSE Linux 8.0 (i386), from userid 511) id C553CBAE6; Tue, 21 Jan 2003 12:02:12 +0300 (MSK) From: Nikita Danilov MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15917.3220.652605.965883@laputa.namesys.com> Date: Tue, 21 Jan 2003 12:02:12 +0300 X-PGP-Fingerprint: 43CE 9384 5A1D CD75 5087 A876 A1AA 84D0 CCAA AC92 X-PGP-Key-ID: CCAAAC92 X-PGP-Key-At: http://wwwkeys.pgp.net:11371/pks/lookup?op=get&search=0xCCAAAC92 To: Julian Elischer Cc: Steve Byan , freebsd-fs@FreeBSD.ORG Subject: Re: JFS vs. Soft Updates (again) (was: Re: large filesystem, journaling filesystem support) In-Reply-To: References: <37CA8FF0-2CA5-11D7-962B-00306548867E@maxtor.com> X-Mailer: VM 7.07 under 21.5 (beta9) "brussels sprouts" XEmacs Lucid Tomato: Mauve Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org Julian Elischer writes: > I hate to enter this argument but.... > > > On Mon, 20 Jan 2003, Steve Byan wrote: > [...] > > > > > If you wish to have writes complete to the media in the order in which > > you issued then, then you must either > > a) disable write caching and not use SCSI command queuing for ordered > > writes > > or > > b) enable write caching but do not use SCSI command queuing, and either > > b1) set the FUA bit in the SCSI CDB and not use command queuing for > > ordered writes, or > > b2) follow the ATA write command with a "flush cache" command > > or > > c) enable write caching and SCSI command queuing, but > > c1) set the FUA bit in the SCSI CDB and ensure the command has the > > "ordered task" attribute in its task tag, so that the command will not > > be reordered. > > > > that is good information > maybe the SCSI and ATA guys can experiment on whether any of these modes > gives us acceptable performance. > Linux reiserfs on SCSI devices can run with write-behind caching, and uses write barriers to write transaction commit records. It has been found that performance in this case is identical to just running (unsafely) with write-behind caching, which is much better than using write-through cache. Sorry, I don't have any numbers on this. > > > > [...] Nikita. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message