Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764848AbZDHMof (ORCPT ); Wed, 8 Apr 2009 08:44:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755261AbZDHMoZ (ORCPT ); Wed, 8 Apr 2009 08:44:25 -0400 Received: from mx1.redhat.com ([66.187.233.31]:35001 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750902AbZDHMoY (ORCPT ); Wed, 8 Apr 2009 08:44:24 -0400 Date: Wed, 8 Apr 2009 08:44:11 -0400 (EDT) From: Mikulas Patocka X-X-Sender: mpatocka@hs20-bc2-1.build.redhat.com To: Lee Revell cc: Ric Wheeler , Theodore Tso , Ric Wheeler , Jens Axboe , device-mapper development , Linux Kernel Mailing List , ak@linux.intel.com, "MASON, CHRISTOPHER" Subject: Re: [dm-devel] Barriers still not passing on simple dm devices... In-Reply-To: <75b66ecd0904051814n353bb69bp76a38e36cac4d3fe@mail.gmail.com> Message-ID: References: <20090324150517.GX27476@kernel.dk> <20090326084205.GG27476@kernel.dk> <20090331104933.GJ5178@kernel.dk> <20090403081131.GP5178@kernel.dk> <49D77AC3.3020207@redhat.com> <20090405012839.GF7553@mit.edu> <49D89C06.1060700@gmail.com> <75b66ecd0904051814n353bb69bp76a38e36cac4d3fe@mail.gmail.com> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1127 Lines: 25 On Sun, 5 Apr 2009, Lee Revell wrote: > On Sun, Apr 5, 2009 at 7:54 AM, Ric Wheeler wrote: > > One thing to point out here is that there are a lot of "servers" in high end > > data centers that do not have UPS backup. Those racks full of 1U and 2U > > boxes that are used to make "grids", "clouds" and so on often are built with > > as much gear as you can stuff in a rack - no batteries or UPS to be seen, so > > they are really quite similar to the normal desktop or home systems that we > > normally run at home :-) > > These days even bargain basement data centers provide UPS functionality for > you, via generator backup and A/B power. I have seen an installation having generator backup, but with another serious flaw --- if someone plugged a computer causing short-circuit, it turned off the circuit breaker for the whole rack :) Mikulas > Lee -- 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/