Re: My superblocks have gone missing, can't reassemble raid5

[Wols Lists <antlists@youngman.org.uk>]

On 19/05/21 18:08, Leslie Rhorer wrote:
> 
> 
> On 5/19/2021 11:41 AM, antlists wrote:
>> On 19/05/2021 15:48, Leslie Rhorer wrote:
>>
>> Because defaults change?
> 
>     Oh, I also don't necessarily know which build of mdadm he is using.
> They might be default on my build but not his.
> 
>>>      Now try running a check on the assembled array:
>>> fsck /dev/md99
>>>
>>>      If that fails, shutdown the array with
>>>
>>> mdadm -S /dev/md99
>>>
>>>      and then try creating the array with a different drive order.
>>> There are only two other possible permutations of three disks.  If
>>> none of those work, you have some more serious problems.
>>
>> And here you are oversimplifying the problem immensely. If those three
>> drives aren't the originals
> 
>     Hang on.  Which drives do you mean?

The drives he originally ran --create on to create the array in the
first place.

The ONLY time you can be reasonably confident that running --create WILL
recover a damaged array is if it is still in its original state - no
drives swapped, no admin changes to the array, AND you're using the same
version of mdadm.

Cheers,
Wol