From: Max Waterman <davidmaxwaterman+kernel@fastmail.co.uk>
To: "Jeff V. Merkey" <jmerkey@wolfmountaingroup.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: io performance...
Date: Wed, 18 Jan 2006 15:06:47 +0800 [thread overview]
Message-ID: <43CDE907.8070508@fastmail.co.uk> (raw)
In-Reply-To: <43CDC607.2040501@wolfmountaingroup.com>
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.
<shrug>
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/
>>>>
>>>
>>
>>
>
next prev parent reply other threads:[~2006-01-18 7:07 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-01-16 7:35 io performance Max Waterman
2006-01-16 7:32 ` Jeff V. Merkey
2006-01-17 13:57 ` Jens Axboe
2006-01-17 19:17 ` Jeff V. Merkey
2006-01-16 8:35 ` Pekka Enberg
2006-01-17 17:06 ` Phillip Susi
2006-01-18 7:24 ` Max Waterman
2006-01-18 15:19 ` Phillip Susi
2006-01-20 5:58 ` Max Waterman
2006-01-20 13:42 ` Ian Soboroff
2006-01-25 6:36 ` Max Waterman
2006-01-25 14:19 ` Ian Soboroff
2006-01-25 13:09 ` Bernd Eckenfels
2006-01-18 3:02 ` Max Waterman
2006-01-18 4:30 ` Jeff V. Merkey
2006-01-18 5:09 ` Max Waterman
2006-01-18 4:37 ` Jeff V. Merkey
2006-01-18 7:06 ` Max Waterman [this message]
2006-01-18 9:21 ` Alan Cox
2006-01-18 15:48 ` Phillip Susi
2006-01-18 16:25 ` Bartlomiej Zolnierkiewicz
2006-01-19 0:48 ` Adrian Bunk
2006-01-19 13:18 ` Max Waterman
[not found] <5vx8f-1Al-21@gated-at.bofh.it>
[not found] ` <5wbRY-3cF-3@gated-at.bofh.it>
[not found] ` <5wdKh-5wF-15@gated-at.bofh.it>
2006-01-19 1:58 ` Robert Hancock
2006-01-19 13:14 ` Max Waterman
2006-01-19 14:08 ` Alan Cox
2006-01-20 4:09 ` Max Waterman
2006-01-20 4:27 ` Alexander Samad
2006-01-20 12:52 ` Alan Cox
2006-01-19 11:39 Al Boldi
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