From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757482AbZHZOLN (ORCPT ); Wed, 26 Aug 2009 10:11:13 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757447AbZHZOLM (ORCPT ); Wed, 26 Aug 2009 10:11:12 -0400 Received: from bee.hiwaay.net ([216.180.54.11]:41814 "EHLO bee.hiwaay.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757445AbZHZOLL (ORCPT ); Wed, 26 Aug 2009 10:11:11 -0400 Date: Wed, 26 Aug 2009 09:11:03 -0500 From: Chris Adams To: Alan Cox Cc: Theodore Tso , linux-kernel@vger.kernel.org Subject: Re: [patch] document flash/RAID dangers Message-ID: <20090826141103.GA1497509@hiwaay.net> References: <20090826134045.GA1516467@hiwaay.net> <20090826144716.486a0d44@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090826144716.486a0d44@lxorguk.ukuu.org.uk> User-Agent: Mutt/1.4i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Once upon a time, Alan Cox said: > > The issues being raised here are not specific to extX, MD RAID, or Linux > > at all; they are problems with non-"enterprise-class" RAID setups. > > There's a reason enterprise-class RAID costs a lot more money than the > > card you can pick up at Fry's. > > And you will still need backups ;) Yep. RAID (of any class) != fail safe. > A long time ago I worked on a fault tolerant news server with dual > alphaserver boxes and a shared disk array. A power system failure took > out both the alpha boxes and the disk controllers and all the disks. Hey, that's not funny! I'm typing this on a dual AlphaServer cluster with a shared disk array (with dual battery backup even), and we had a power failure at the NOC yesterday (that then tripped a breaker, although it was between the generator and the UPS, so nothing went down). No matter how redundant you make things, a "no single point of failure" setup still can fail, often in "interesting" ways that nobody anticipated. -- Chris Adams Systems and Network Administrator - HiWAAY Internet Services I don't speak for anybody but myself - that's enough trouble.