md raid 5 not working

[Bill Davidsen]

Kanwar Ranbir Sandhu wrote:
> On Sat, 2009-12-26 at 15:28 -0500, Kanwar Ranbir Sandhu wrote:
>> My Linux RAID skills/experience aren't that deep, so I'm not sure how to
>> fix this.  I'd appreciate any pointers.
>>
>> Some details:
> 
>>    Device Boot      Start         End      Blocks   Id  System
>> /dev/sdb1               1       60801   488384001   fd  Linux raid autodetect
> 
>>    Device Boot      Start         End      Blocks   Id  System
>> /dev/sdd1               1       60801   488384001   fd  Linux raid autodetect
> 
>>    Device Boot      Start         End      Blocks   Id  System
>> /dev/sde1               1       60801   488384001   fd  Linux raid autodetect
> 
> Solved my problem!
> 
> As you can see here, the md superblock is on the first primary partition
> of each of these drives.  But, Linux wasn't seeing these partitions.  A
> simple 'ls -l /dev/sd*' only showed me /dev/sdb, /dev/sdd, and /dev/sde.
> The reason I provided mdadm details on these drives was because I
> couldn't see /dev/sdb1, etc.  I couldn't give md information on the
> partitions.
> 
> I realized I had once used the entire drives in a md RAID 5 set instead
> of building the RAID 5 on partitions.  I had outdated md superblocks
> on /dev/sd[bde]!  I suppose when I rebuilt the array properly, I didn't
> wipe the drives completely.  Basically, the old md superblocks were
> confusing the kernel.
> 
> To fix this, I ran the following from the rescue CD:
> 
> mdadm --zero-superblock --force /dev/sdb
> mdadm --zero-superblock --force /dev/sdd
> mdadm --zero-superblock --force /dev/sde
> 
> When I rebooted, /dev/md3 was detected properly and came up without any
> problems.  Sweet!
> 
> Thanks to everyone that replied.  I didn't think I could solve this one
> on my own, but the man page + my realization of what was going on helped
> immensely.
> 
For future reference there is also the linux-raid mailing list which handles 
issue regardless of release.

-- 
Bill Davidsen <davidsen at tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot