On 09/24/2013 07:38 PM, Martin Wilck wrote:

I tried your scenario on HW with LSI fake RAID and encountered the same
problem you had. I have come up with a patch that I've just posted ("Fix
mdadm --add for LSI fake RAID" and follow-ups).

Please try if this patch fixes your problem. To be precise, with this
patch applied, mdadm /dev/md127 --add /dev/sdX should work again. You
should be able to run this on your currently broken system if you
somehow manage to transfer the updated mdadm and mdmon executables to
that system, run mdmon --takeover /dev/md127, and then remove/add sdX again.

One more remark: You are probably better off for now by doing operations
like re-adding diks in your system's BIOS RAID setup tool. The reason is
that we can't be sure yet that the structures we set up are correctly
understood by the BIOS - you may successfully add the disk with mdadm,
but at the next boot the BIOS may not understand the data and break it
again.

For IMSM we were in the lucky situation that the BIOS vendor himself
provided the code. For DDF, figuring this out is a cumbersome
trial-and-error process.

Martin