Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030263AbWARHHB (ORCPT ); Wed, 18 Jan 2006 02:07:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030271AbWARHHB (ORCPT ); Wed, 18 Jan 2006 02:07:01 -0500 Received: from out4.smtp.messagingengine.com ([66.111.4.28]:1504 "EHLO out4.smtp.messagingengine.com") by vger.kernel.org with ESMTP id S1030263AbWARHHA (ORCPT ); Wed, 18 Jan 2006 02:07:00 -0500 X-Sasl-enc: pHz7eFH5KFhSzNEznw8KSsg5RJksJRpX6IanBV4orEF/ 1137568014 Message-ID: <43CDE907.8070508@fastmail.co.uk> Date: Wed, 18 Jan 2006 15:06:47 +0800 From: Max Waterman User-Agent: Thunderbird 1.6a1 (Macintosh/20060116) MIME-Version: 1.0 To: "Jeff V. Merkey" 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> <43CDC607.2040501@wolfmountaingroup.com> In-Reply-To: <43CDC607.2040501@wolfmountaingroup.com> 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: 1432 Lines: 65 Jeff V. Merkey wrote: > 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. Ok, thanks for clearing that up, though I now wonder why the message is there. Max. > > 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/