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From: "Kristleifur Daðason" <kristleifur@gmail.com>
To: linux-raid@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: BUG:write data to degrade raid5
Date: Fri, 19 Mar 2010 18:26:18 +0000	[thread overview]
Message-ID: <73e903671003191126l6c0bed69q69c32bf37922690d@mail.gmail.com> (raw)
In-Reply-To: <73e903671003191123h1b7e1196v336265842f1b29e5@mail.gmail.com>

On Fri, Mar 19, 2010 at 6:20 PM, Joachim Otahal <Jou@gmx.net> wrote:
> jin zhencheng schrieb:
>>
>> hi;
>>
>> i use kernel is 2.6.26.2
>>
>> what i do as follow:
>>
>> 1, I create a raid5:
>> mdadm -C /dev/md5 -l 5 -n 4 /dev/sda /dev/sdb /dev/sdc  /dev/sdd
>> --metadata=1.0 --assume-clean
>>
>> 2, dd if=/dev/zero of=/dev/md5 bs=1M&
>>
>> write data to this raid5
>>
>> 3, mdadm --manage /dev/md5 -f /dev/sda
>>
>> 4 mdadm --manage  /dev/md5 -f /dev/sdb
>>
>> if i faild 2 disks ,then the OS kernel display OOP error and kernel down
>>
>> do somebody know why ?
>>
>> Is MD/RAID5 bug ?
>>
>
> RAID5 can only tolerate ONE drive to fail of ALL members. If you want to be
> able to fail two drives you will have to use RAID6 or RAID5 with one
> hot-spare (and give it time to rebuild before failing the second drive).
> PLEASE read the documentation on raid levels, like on wikipedia.
>

That is true,

but should we get a kernel oops and crash if two RAID5 drives are
failed? (THAT part looks like a bug!)

Jin, can you try a newer kernel, and a newer mdadm?

-- Kristleifur
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  parent reply	other threads:[~2010-03-19 18:26 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-19 10:29 BUG:write data to degrade raid5 jin zhencheng
2010-03-19 18:20 ` Joachim Otahal
2010-03-19 18:30   ` Robin Hill
     [not found]   ` <73e903671003191123h1b7e1196v336265842f1b29e5@mail.gmail.com>
2010-03-19 18:26     ` Kristleifur Daðason [this message]
2010-03-19 18:37     ` Joachim Otahal
2010-03-21 10:29       ` jin zhencheng
2010-03-21 13:04         ` Henrique de Moraes Holschuh
2010-03-22  1:41           ` jin zhencheng
2010-03-20 15:50 ` Bill Davidsen
2010-03-23  3:16 ` Neil Brown

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