Garbled Data on Drive: RAID/non-RAID confusion? [COLUG]

[Rick Troth]

On Sun, 7 Jan 2007, Jim wrote:
> My _vague_ recollection is that software RAID uses some of the
> beginning of the drive for some RAID overhead information.
 ...

I'm new to the RAID game,
but what I've seen puts that magic at the END of each volume.
If that is correct, then RAID bits do not interfere with
partition tables, if any.

But I'm in the habit of occasionally NOT partitioning a disk,
especially if I were going to feed it to RAID as a PV.
(Inconsequential amount of space recovered, but it's the principle
of reducing unused layers.)  So I can imagine a filesystem on Kent's
entire disk blowing away the partition table.  Or if it was in fact
part of a RAID set, similar obliteration of the partn table
but not something that could be mounted on its own.

 ...
> Back to your confused drive. If it has been written to
> both with and without RAID, it might have been written to
> in wrong places, messing up partitions, so even when you
> find the actual beginnings of partitions, don't be
> surprised if fsck complains.

Indeed!
In which case if one or more partitions were used by/for RAID
they would be unusable on their own.

-- R;