[CentOS] *very* ugly mdadm issue

Tue Sep 2 18:05:18 UTC 2014
Keith Keller <kkeller at wombat.san-francisco.ca.us>

On 2014-09-02, Warren Young <warren at etr-usa.com> wrote:
> On 8/29/2014 14:26, m.roth at 5-cent.us wrote:
>>
>> Note that we did this on *raw*, unpartitioned drives (not my idea).
>
> Nothing wrong with that, particularly with big "midden" volumes like 
> this one.

Indeed--hardware RAID controllers don't partition their drives before
creating their arrays.

> I don't see why it matters that your /dev/sdd partitioning is different 
> from your /dev/sdc.  When you told it to blast /dev/sdc with the 
> contents of /dev/sdd, it should have copied the partitioning, too.

If it was an rsync, then partitioning would not have been copied, just
the filesystem contents.

As for the OP, while this certainly doesn't seem to be a problem with
mdadm specifically (or linux md in general), the folks on the linux RAID
mailing list may be able to help you recover (I, too, seldom use linux
md, and do not know it well enough to be helpful).

http://vger.kernel.org/vger-lists.html#linux-raid

--keith

-- 
kkeller at wombat.san-francisco.ca.us