Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753882AbZAEJpX (ORCPT ); Mon, 5 Jan 2009 04:45:23 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752561AbZAEJpJ (ORCPT ); Mon, 5 Jan 2009 04:45:09 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:50944 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752288AbZAEJpG (ORCPT ); Mon, 5 Jan 2009 04:45:06 -0500 Date: Mon, 5 Jan 2009 10:45:04 +0100 From: Pavel Machek To: "Martin K. Petersen" Cc: Rob Landley , kernel list , Andrew Morton , tytso@mit.edu, mtk.manpages@gmail.com, rdunlap@xenotime.net, linux-doc@vger.kernel.org Subject: Re: document ext3 requirements Message-ID: <20090105094504.GB27199@atrey.karlin.mff.cuni.cz> References: <20090103123813.GA1512@ucw.cz> <200901041349.49906.rob@landley.net> <20090104225545.GF1913@elf.ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1440 Lines: 34 > >>>>> "Pavel" == Pavel Machek writes: > > Pavel> Does this sound like a fair summary? > > Pavel> Sector writes are atomic (ATOMIC-SECTORS) > Pavel> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > I'd just like to point out that the all-or-nothing hardware sector > atomity thing is -- to a large extent -- a myth. It is a myth that linux filesystems depend on for safe operation :-(. > It is mostly true on SCSI class devices because various UNIX, RAID array > and database vendors have spent many years leaning very hard on the > drive manufacturers to make it so. > > But it's not a hard guarantee, you can't get it in writing, and it's not > in any of the standards. Hybrid drives with flash had potential to > close that particular loophole but those appear to be dead in the water. So "in practice it works but vendors will not guarantee that"? How much true is it for normal SATA drives? Are there some tests I can just run on a machine, powercycle it few times, and it tells me if my disk is non-ATOMIC-SECTORS? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/