Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755712AbZC3Oov (ORCPT ); Mon, 30 Mar 2009 10:44:51 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754424AbZC3Ook (ORCPT ); Mon, 30 Mar 2009 10:44:40 -0400 Received: from rtr.ca ([76.10.145.34]:39307 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751520AbZC3Ooj (ORCPT ); Mon, 30 Mar 2009 10:44:39 -0400 Message-ID: <49D0DAD3.6030507@rtr.ca> Date: Mon, 30 Mar 2009 10:44:35 -0400 From: Mark Lord Organization: Real-Time Remedies Inc. User-Agent: Thunderbird 2.0.0.21 (X11/20090318) MIME-Version: 1.0 To: Ric Wheeler Cc: "Andreas T.Auer" , Alan Cox , Theodore Tso , Stefan Richter , Jeff Garzik , Linus Torvalds , Matthew Garrett , Andrew Morton , David Rees , Jesper Krogh , Linux Kernel Mailing List Subject: Re: Linux 2.6.29 References: <49CD7B10.7010601@garzik.org> <49CD891A.7030103@rtr.ca> <49CD9047.4060500@garzik.org> <49CE2633.2000903@s5r6.in-berlin.de> <49CE3186.8090903@garzik.org> <49CE35AE.1080702@s5r6.in-berlin.de> <49CE3F74.6090103@rtr.ca> <20090329231451.GR26138@disturbed> <20090330003948.GA13356@mit.edu> <49D0710A.1030805@ursus.ath.cx> <20090330100546.51907bd2@the-village.bc.nu> <49D0A3D6.4000300@ursus.ath.cx> <49D0AA4A.6020308@redhat.com> <49D0CDBA.7040702@rtr.ca> <49D0D08E.3090100@redhat.com> In-Reply-To: <49D0D08E.3090100@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1080 Lines: 28 Ric Wheeler wrote: > Mark Lord wrote: >> Ric Wheeler wrote: .. >> The kernel can crash, and the drives, in practice, will still >> flush their caches to media by themselves. Within a second or two. > > Even with desktops, I am not positive that the drive write cache > survives a kernel crash without data loss. If I remember correctly, > Chris's tests used crashes (not power outages) to display the data > corruption that happened without barriers being enabled properly. .. Linux f/s barriers != drive write caches. Drive write caches are an almost total non-issue for desktop users, except on the (very rare) event of a total, sudden power failure during extended write outs. Very rare. Yes, a huge problem for server farms. No question. But the majority of Linux systems are probably (still) desktops/notebooks. Cheers -- 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/