Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755156AbYCMNaZ (ORCPT ); Thu, 13 Mar 2008 09:30:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752139AbYCMNaQ (ORCPT ); Thu, 13 Mar 2008 09:30:16 -0400 Received: from mexforward.lss.emc.com ([128.222.32.20]:18721 "EHLO mexforward.lss.emc.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751937AbYCMNaP (ORCPT ); Thu, 13 Mar 2008 09:30:15 -0400 Message-ID: <47D92BBB.6000203@emc.com> Date: Thu, 13 Mar 2008 09:27:23 -0400 From: Ric Wheeler Reply-To: ric@emc.com User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Lars Marowsky-Bree CC: Daniel Phillips , Alan Cox , Grzegorz Kulewski , linux-kernel@vger.kernel.org Subject: Re: [ANNOUNCE] Ramback: faster than a speeding bullet References: <200803092346.17556.phillips@phunq.net> <200803110414.40954.phillips@phunq.net> <20080311112329.GR1581@marowsky-bree.de> <200803110450.19390.phillips@phunq.net> <20080311215601.GM23784@marowsky-bree.de> In-Reply-To: <20080311215601.GM23784@marowsky-bree.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-PMX-Version: 4.7.1.128075, Antispam-Engine: 2.5.1.298604, Antispam-Data: 2007.8.30.53115 X-PerlMx-Spam: Gauge=, SPAM=0%, Reason='EMC_BODY_1+ -3, EMC_BODY_PROD_2+ -3, EMC_FROM_0+ -3, __CT 0, __CTE 0, __CT_TEXT_PLAIN 0, __HAS_MSGID 0, __MIME_TEXT_ONLY 0, __MIME_VERSION 0, __SANE_MSGID 0, __USER_AGENT 0' X-Tablus-Inspected: yes X-Tablus-Classifications: public X-Tablus-Action: allow Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1783 Lines: 42 Lars Marowsky-Bree wrote: > On 2008-03-11T03:50:18, Daniel Phillips wrote: > >>> as well. In fact, the most common reason for unorderly shutdowns are >>> kernel crashes, not power failures in my experience. >> What are you doing to your kernel? > > I guess I'm being really vicious to them: I expose it to customers and > the real world. > > My own servers also have uptimes of >400 days sometimes, and I wonder > what customers do to the poor things. > > And yes, I'm not saying I don't see your point for specialised > deployments (filesystems which are easy to rebuild from scratch), but > transactional integrity is a requirement I'd rank really high on the > desirable list of features if I was you. > >>> So "perfectly reliable if UPS power does not fail" seems a bit over the >>> top. >> It works for EMC :-) > > Where they control the hardware and run a rather specialized OS as well, > not a general purpose system like Linux on "commodity" hardware ;-) Actually, in Centera we use generic hardware with a fairly normal kernel which has strategic backports from upstream (libata, nic drivers, etc). No UPS in the picture. Data integrity is protected by working with the application team to insure they understand when data is safely on the disk platter and working with IO & FS people to try and make sure we don't lie to them (too much ) about that promise. The centera boxes are tested with power failure & error injection and by all of our customers in all those ways customers do ;-) ric -- 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/