Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030239AbWARFNT (ORCPT ); Wed, 18 Jan 2006 00:13:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030250AbWARFNT (ORCPT ); Wed, 18 Jan 2006 00:13:19 -0500 Received: from c-67-177-35-222.hsd1.ut.comcast.net ([67.177.35.222]:28545 "EHLO ns1.utah-nac.org") by vger.kernel.org with ESMTP id S1030239AbWARFNT (ORCPT ); Wed, 18 Jan 2006 00:13:19 -0500 Message-ID: <43CDC607.2040501@wolfmountaingroup.com> Date: Tue, 17 Jan 2006 21:37:27 -0700 From: "Jeff V. Merkey" User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040510 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Max Waterman Cc: linux-kernel@vger.kernel.org Subject: Re: io performance... References: <43CB4CC3.4030904@fastmail.co.uk> <43CDAFE3.8050203@fastmail.co.uk> <43CDC44E.6080808@wolfmountaingroup.com> <43CDCD9F.5050500@fastmail.co.uk> In-Reply-To: <43CDCD9F.5050500@fastmail.co.uk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1252 Lines: 55 Max Waterman wrote: > Jeff V. Merkey wrote: > >> Max Waterman wrote: >> >>> One further question. I get these messages 'in' dmesg : >>> >>> sda: asking for cache data failed >>> sda: assuming drive cache: write through >>> >>> How can I force it to be 'write back'? >> >> >> >> >> Forcing write back is a very bad idea unless you have a battery >> backed up RAID controller. > > > We do. > > In any case, I wonder what the consequences of assuming 'write > through' when the array is configured as 'write back'? Is it just > different settings for different caches? It is. This is something that should be configured in a RAID controller. OS should always be write through. Jeff > > Max. > >> Jeff >> >>> >>> Max. >>> - >>> 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/ >>> >> > > - 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/