Re: In Trouble--Please Help! (was Re: Can't add disk to failed raid array)

[Paul Waldo <pwaldo@waldoware.com>]

On Sunday 23 July 2006 07:25, Neil Brown wrote:
> On Sunday July 23, pwaldo@waldoware.com wrote:
> > Please, please! I am dead in the water!
> >
> > To recap, I have a RAID6 array on a Fedora Core 5 system, using
> > /dev/hd[acdeg] 2 and /dev/sd[ab]2.  /dev/hdd went bad so I replaced the
> > drive and tried to add it back to the array.  Here is what happens:
> >
> > #mdadm --assemble /dev/md1 /dev/hd[acdeg]2 /dev/sd[ab]2
> > mdadm: no RAID superblock on /dev/hdd2
> > mdadm: /dev/hdd2 has no superblock - assembly aborted
> >
> > I also tried assembling without the new drive:
> > #mdadm --assemble /dev/md1 /dev/hd[aceg]2 /dev/sd[ab]2
> > mdadm: failed to RUN_ARRAY /dev/md1: Input/output error
> >
> > Forgive me if the messages are not exactly correct, as I am booted into
> > the FC rescue disk and I am transcribing what I see to another computer.
> >
> > How can I get mdadm to use the new drive?  Am I completely fscked? 
> > Thanks in advance for any help!!!!
>
> Sorry for not following through on this earlier.
> I think I know what the problem is.
>
>  From the "-E" output you have me :
>      Device Size : 155308288 (148.11 GiB 159.04 GB)
>
>  From the fdisk output in the original email:
>
> [root@paul ~]# fdisk -l /dev/hdd
>
> Disk /dev/hdd: 160.0 GB, 160029999616 bytes
> 255 heads, 63 sectors/track, 19455 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
>
>    Device Boot      Start         End      Blocks   Id  System
> /dev/hdd1               1         122      979933+  fd  Linux raid
> autodetect /dev/hdd2             123       19455   155292322+  fd  Linux
> raid autodetect
>
>
> Notice that hdd2 is 155292322, but the device needs to be
> 155308288.  It isn't quite big enough.
> mdadm should pick this up, but obviously doesn't, and the error message
> isn't at all helpful.
> I will fix that in the next release.
> For now, repartition your drive so that hdd2 is slightly larger.
>
> NeilBrown

Hi Neil,

Thanks for the quick reply.  I tried your suggestion.  I now see 
that /dev/hda2 (good partition) is 155308387 blocks.  I 
repartitioned /dev/hdd such that /dev/hdd2 is also 155308387, but I still get 
the message about no superblock on hdd2 :-(.  I used --force.

Paul