From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751314AbWAQQIb (ORCPT ); Tue, 17 Jan 2006 11:08:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751308AbWAQQIb (ORCPT ); Tue, 17 Jan 2006 11:08:31 -0500 Received: from jose.lug.udel.edu ([128.175.60.112]:27307 "EHLO jose.lug.udel.edu") by vger.kernel.org with ESMTP id S1751299AbWAQQIa (ORCPT ); Tue, 17 Jan 2006 11:08:30 -0500 Date: Tue, 17 Jan 2006 11:08:30 -0500 To: Michael Tokarev Cc: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 000 of 5] md: Introduction Message-ID: <20060117160829.GA16606@lug.udel.edu> References: <20060117174531.27739.patches@notabene> <43CCA80B.4020603@tls.msk.ru> <20060117095019.GA27262@localhost.localdomain> <43CCD453.9070900@tls.msk.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <43CCD453.9070900@tls.msk.ru> User-Agent: Mutt/1.5.11 From: ross@jose.lug.udel.edu (Ross Vandegrift) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 17, 2006 at 02:26:11PM +0300, Michael Tokarev wrote: > Raid code is already too fragile, i'm afraid "simple" I/O errors > (which is what we need raid for) may crash the system already, and > am waiting for the next whole system crash due to eg superblock > update error or whatnot. I think you've got some other issue if simple I/O errors cause issues. I've managed hundreds of MD arrays over the past ~ten years. MD is rock solid. I'd guess that I've recovered at least a hundred disk failures where data was saved by mdadm. What is your setup like? It's also possible that you've found a bug. > I saw all sorts of failures due to > linux softraid already (we use it here alot), including ones > which required complete array rebuild with heavy data loss. Are you sure? The one thing that's not always intuitive about MD - a faild array often still has your data and you can recover it. Unlike hardware RAID solutions, you have a lot of control over how the disks are assembled and used - this can be a major advantage. I'd say once a week someone comes on the linux-raid list and says "Oh no! I accidently ruined my RAID array!". Neil almost always responds "Well, don't do that! But since you did, this might help...". -- Ross Vandegrift ross@lug.udel.edu "The good Christian should beware of mathematicians, and all those who make empty prophecies. The danger already exists that the mathematicians have made a covenant with the devil to darken the spirit and to confine man in the bonds of Hell." --St. Augustine, De Genesi ad Litteram, Book II, xviii, 37