Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757349AbYCMTQZ (ORCPT ); Thu, 13 Mar 2008 15:16:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757002AbYCMTP0 (ORCPT ); Thu, 13 Mar 2008 15:15:26 -0400 Received: from mexforward.lss.emc.com ([128.222.32.20]:51666 "EHLO mexforward.lss.emc.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756964AbYCMTPZ (ORCPT ); Thu, 13 Mar 2008 15:15:25 -0400 Message-ID: <47D97C9E.303@emc.com> Date: Thu, 13 Mar 2008 15:12:30 -0400 From: Ric Wheeler Reply-To: ric@emc.com User-Agent: Thunderbird 2.0.0.9 (X11/20071031) MIME-Version: 1.0 To: Daniel Phillips CC: Lars Marowsky-Bree , Alan Cox , Grzegorz Kulewski , linux-kernel@vger.kernel.org Subject: Re: [ANNOUNCE] Ramback: faster than a speeding bullet References: <200803092346.17556.phillips@phunq.net> <20080311215601.GM23784@marowsky-bree.de> <47D92BBB.6000203@emc.com> <200803131202.48135.phillips@phunq.net> In-Reply-To: <200803131202.48135.phillips@phunq.net> 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: 1755 Lines: 43 Daniel Phillips wrote: > On Thursday 13 March 2008 06:27, Ric Wheeler wrote: >>>>> 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 ;-) > > Hi Ric, > > Right, so Linux has gotten to the point where it competes with purpose- > built embedded software in reliability. Not quite there, but close > enough for mission-critical. This is our case, but we have been working for quite a while to enhance the reliability of the io stack & file systems. It also helps to be very careful to select hardware components with mature, open source & natively integrated drivers ;-) > > I was not thinking of Centera when I mentioned the UPS though... > > Daniel No problem, we certainly have many boxes with built in ups hardware ;-) 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/