hi Joachim Otahal:

ths for your test on "Debian 2.6.26-21lenny4".
if you want to see the oop ,you should always write to the raid5 ,and
pull 2 disks out.maybe you can see the error

i think no matter what i do ,even if i pull out all the disk , kernel
should not oop.


On Sat, Mar 20, 2010 at 2:37 AM, Joachim Otahal [off-list ref] wrote:

Kristleifur Dağason schrieb:

quoted

On Fri, Mar 19, 2010 at 6:20 PM, Joachim Otahal <Jou@gmx.net
<mailto: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

You are probably right.
My kernel version is "Debian 2.6.26-21lenny4", and I had no oopses during my
hot-plug testing one the hardware I use md on. I think it may be the driver
for his chips.

Jin:

Did you really use the whole drives for testing or loopback files or
partitions on the drives? I never did my hot-plug testings with whole drives
being in an array, only with partitions.

Joachim Otahal