Is there a tool to examine raw metadata?

Is there a tool to examine raw metadata?

[Veedar Hokstadt]

Greetings,
Consider a 3 drive RAID5 where each drive has lost it's partitioning
info. Running mdadm -E does not find a superblock. But using hexedit
an mdadm superblock can be found in tact near the end of each drive.

Is there perhaps a tool I can point at the superblock to decode it? Or
trick mdadm into reporting the contents of the superblock?

I know I can look at the superblock format doc and translate it by
hand but I was hoping for an easier way.   Thanks for any help.  -V

Re: Is there a tool to examine raw metadata?

[NeilBrown]

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On Wed, 20 Nov 2013 13:26:10 -0500 Veedar Hokstadt <veedar@gmail.com> wrote:

> Greetings,
> Consider a 3 drive RAID5 where each drive has lost it's partitioning
> info. Running mdadm -E does not find a superblock. But using hexedit
> an mdadm superblock can be found in tact near the end of each drive.
> 
> Is there perhaps a tool I can point at the superblock to decode it? Or
> trick mdadm into reporting the contents of the superblock?
> 
> I know I can look at the superblock format doc and translate it by
> hand but I was hoping for an easier way.   Thanks for any help.  -V
> --
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If you use losetup to create a device pointing to the original but with an
offset to match where you think the partition was, then run "mdadm -E" on the
loop device.

You could probably do:

 for i in {1..1000}
 do
  losetup -o $i /dev/loop0 /dev/whatever
  echo $i
  mdadm -E /dev/loop0
  mdadm -d /dev/loop0
 done

NeilBrown

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