Fedora 11 and dmraid with intel - problems

Dan Williams dan.j.williams at intel.com
Wed Nov 11 03:56:18 UTC 2009

On Tue, Nov 10, 2009 at 6:15 PM, Michael Cronenworth <mike at cchtml.com> wrote:
> On 11/10/2009 06:16 PM, Dan Williams wrote:
>> Newer dmraid releases may handle the rebuild case better.  However, I
>> suspect you should be able to rebuild it with mdadm via a Live USB/CD
>> image.  This should allow you to get the array back into a state that
>> will make the dmraid in your Fedora 11 environment happy.
>> 0/ If you haven't already, get a backup of your one good drive in case
>> something goes wrong with the following steps.
>> 1/ Boot to a Live USB/CD image with a recent version of mdadm (>= 3.0).
>> 2/ Make sure that dmraid has not assembled the disks
>> 3/ mdadm -A /dev/md/imsm /dev/sda # add the one good drive to an 'imsm
>> container'
>> 4/ mdadm -I /dev/md/imsm # start the container
>> 5/ cat /proc/mdstat # verify that your raid volume was started in degraded
>> mode
>> 6/ mdadm --add /dev/md/imsm /dev/sdb # add the new disk to the
>> container which starts the rebuild
>> 7/<wait for rebuild to complete>
>> 8/ mdadm -E /dev/sda # dump the metadata and check that it is no
>> longer marked 'Degraded'/'Rebuild'
>> 9/ mdadm -Ss # stop the array
>> 10/ Boot back into Fedora 11 and let dmraid assemble the array normally.
> I ended up nuking the fakeraid and reinstalled using Linux software raid.

Nothing fake about it, you are using the same software raid1 driver
that the mdadm-3.0 'imsm' support uses.  :-)  I personally prefer the
generic terms 'biosraid' or just 'software raid'.

> Now I have two partitions: one for /boot, one for an LVM(root and swap).
> Both in RAID1.

That's a sane choice for raid1 just make sure you have grub installed
on each disk so there are no surprises when you remove a disk.


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