From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265755AbTFSQm1 (ORCPT ); Thu, 19 Jun 2003 12:42:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265834AbTFSQm1 (ORCPT ); Thu, 19 Jun 2003 12:42:27 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:24506 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S265755AbTFSQm0 (ORCPT ); Thu, 19 Jun 2003 12:42:26 -0400 Message-ID: <3EF1EB2E.8010702@pobox.com> Date: Thu, 19 Jun 2003 12:56:14 -0400 From: Jeff Garzik Organization: none User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.2.1) Gecko/20021213 Debian/1.2.1-2.bunk X-Accept-Language: en MIME-Version: 1.0 To: "Cress, Andrew R" CC: "'Matthias Andree'" , Linux-Kernel mailing list Subject: Re: SCSI Write Cache Enable in 2.4.20? References: In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Cress, Andrew R wrote: > IMO, it isn't "necessary", but it is very desirable, and should be the > default, to disable write cache on SCSI disks for any system that is > concerned about reliability. This sounds like a bug, either in an application, or in Linux kernel's scsi disk implementation. Data is only guaranteed to be written onto disk following an fsync(2)-like operation in the application. And in turn, it is the Linux kernel's responsibility to ensure that such a flush is propagated all the down to the low-level driver, in my opinion. Sophisticated hosts can have barriers, and "dumb" hosts can simply call the drive's flush-cache / sync-cache command. Jeff