Message-ID: <43CDCD9F.5050500@fastmail.co.uk>
Date: Wed, 18 Jan 2006 13:09:51 +0800
From: Max Waterman <davidmaxwaterman+kernel@fastmail.co.uk>
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To: "Jeff V. Merkey" <jmerkey@wolfmountaingroup.com>
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>
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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?

Max.

> Jeff
> 
>>
>> Max.
>> -
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