Re: Broken array, trying to assemble enough to copy data off

[Phil Turmel <philip@turmel.org>]

On 10/10/2013 12:20 PM, Digimer wrote:
>> Phil
> 
> Ya, I have no plan at all to use these drives or the server they came
> from anymore. In fact, they've already been replaced. :)

That's good.

> I tried the --assemble --force (and --assemble --force --run) without
> success. It fails saying that sde2 thinks sdb2 has failed, leaving two
> dead members. If I try to start with just sd[bcd], it says that it has
> two drives and one spare, so still refuses to start.

Ok.

> Any other options/ideas? I'm not in any rush, so I am happy to test things.

Well, you have rock-solid knowledge of the device order and array
parameters.  So a --create operation is the next step.  Given that sdd2
is marked as spare, and therefore of unknown value, I'd leave it out.

mdadm --stop /dev/md1
mdadm --create --level=5 -n 4 --chunk=512 /dev/md1 \
	/dev/sd{c,e,b}2 missing

(--assume-clean isn't needed when creating a degraded raid5)

The brace syntax is needed, not brackets, as the order matters.

After creation, use mdadm -E to verify the Data Offset is 2048.  If not,
get a new version of mdadm that lets you specify it.

Only after that should you use "fsck -n" to verify your filesystem and
mount it.

HTH,

Phil