Re: array went wonky

[Phil Turmel <philip@turmel.org>]

On 04/30/2013 02:20 AM, Sam Bingner wrote:
> On Apr 29, 2013, at 4:33 PM, "Gimpbully" <gimpbully@gmail.com>
> wrote:
>> On Apr 13, 2013, at 7:20 AM, Sam Bingner <sam@bingner.com> wrote:
>> 
>>> After that you can try to recreate the array with the proper
>>> order (sdc1, sdb1, sde1, missing, sda1) and copy data off or add
>>> the spare in again depending on if you were able to recover all
>>> the data wih GNU ddrescue.
>> 
>> 
>> What do you mean recreate?  what's the specific command?  something
>> like:
>> mdadm --create --assume-clean --level=5 --raid-devices=5 /dev/md127
>> /dev/sdc1 /dev/sdb1 /sdv/sde1 missing  /dev/sda1
> 
> Don't recreate it - I said the wrong thing... You want to do an
> assemble on them with force if possible... Recreate is last ditch and
> make sure you have another copy if you do the previous command in
> case it doesn't work right due to offsets etc...
> 
> try:
> mdadm --stop /dev/md127
> mdadm --assemble --force /dev/md127 /dev/sd{c,b,e,a}1

Yes.

> If you DO need to recreate it, what you showed looks correct.

NO!

The OP has *not* shared sufficient information on the array members to
say that.  Since it has "worked for years", the odds of an offset error
is *very* high.  Chunk size defaults are also likely to be different.

*Complete* output of "mdadm -E" for the array members is needed before
any "--create" operation is attempted.  Plus the distro info, kernel
version, and mdadm version .

Phil