Re: Cannot start array on disk

[Phil Turmel <philip@turmel.org>]

Hi Amit,

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On 07/19/2016 10:52 PM, Bhatia Amit wrote:
> Hi Phil
> 
> One more thing. When the enclosure became inaccesible in June 2016,
> WDC gave me a new unit with drives. I dont remember for sure, but I
> think I first replaced drive A from new enclosure with the Drive A
> (currently in discussion) from old enclosure, hoping new unit would
> reconfigure based on info from old drive. But I was not able to
> access the unit. Then I put back the two new drives back in new
> enclosure, configured new unit for RAID1 and then replaced the drive
> A again with the drive A from old enclosure, but again no luck
> accessing it (Error Message=Unable to mount). Since the default
> configuration of a new configuration is Striping and not RAID1,
> probably the first action (replacing drive A before configuring new
> unit for RAID1), might have been the cause why this drive A shows as
> RAID=linear, rather than RAID1.

That could explain it, but I would have expected your mount of /dev/sdc4
to succeed.  Your dmesg excerpt clearly shows a raid1 binding on
partition 4, so the metadata on the drive you are examining must be
wrong.  The only way I know for that to happen is if there are multiple
superblocks on the drive, and a plain examine is finding the v1.0
metadata first.

I'm not sure if this is supported, by try specifying the version along
with --examine for each of v0.90, v1.0, v1.1, and v1.2 to see if any
difference shows.  Paste the results from each.

Phil