From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932578AbZHYXyK (ORCPT ); Tue, 25 Aug 2009 19:54:10 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932477AbZHYXyJ (ORCPT ); Tue, 25 Aug 2009 19:54:09 -0400 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:60467 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932466AbZHYXyH (ORCPT ); Tue, 25 Aug 2009 19:54:07 -0400 Date: Wed, 26 Aug 2009 01:53:59 +0200 From: Pavel Machek To: Ric Wheeler Cc: Theodore Tso , Florian Weimer , Goswin von Brederlow , Rob Landley , kernel list , Andrew Morton , mtk.manpages@gmail.com, rdunlap@xenotime.net, linux-doc@vger.kernel.org, linux-ext4@vger.kernel.org, corbet@lwn.net Subject: Re: [patch] ext2/3: document conditions when reliable operation is possible Message-ID: <20090825235359.GJ4300@elf.ucw.cz> References: <20090824230036.GK29763@elf.ucw.cz> <20090825000842.GM17684@mit.edu> <20090825094244.GC15563@elf.ucw.cz> <4A93E908.6050908@redhat.com> <20090825211515.GA3688@elf.ucw.cz> <4A9468E8.607@redhat.com> <20090825225114.GE4300@elf.ucw.cz> <4A946DD1.8090906@redhat.com> <20090825232601.GF4300@elf.ucw.cz> <4A947682.2010204@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A947682.2010204@redhat.com> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Why don't you hold all of your most precious data on that single S-ATA > drive for five year on one box and put a second copy on a small RAID5 > with ext3 for the same period? > > Repeat experiment until you get up to something like google scale or the > other papers on failures in national labs in the US and then we can have > an informed discussion. I'm not interested in discussing statistics with you. I'd rather discuss fsync() and storage design issues. ext3 is designed to work on single SATA disks, and it is not designed to work on flash cards/degraded MD RAID5s, as Ted acknowledged. Because that fact is non obvious to the users, I'd like to see it documented, and now have nice short writeup from Ted. If you want to argue that ext3/MD RAID5/no UPS combination is still less likely to fail than single SATA disk given part fail probabilities, go ahead and present nice statistics. Its just that I'm not interested in them. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html