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

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

On 19/05/2021 15:48, Leslie Rhorer wrote:
>      Then I would try recreating the RAID based upon the earlier Examine 
> report:
> 
> mdadm -C -f -n 3 -l 5 -e 1.2 -c 512 -p ls /dev/md99 /dev/loop2 
> /dev/loop0 /dev/loop1
> 
>      You may notice some of the command switches are defaults.  Remember 
> what I said about a belt and suspenders?  Personally, in such a case I 
> would not rely on defaults.

Because defaults change?
> 
>      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, then the chances are HIGH that a simple 
re-assembly/creation is going to fail your simplistic scenario.

That said, I couldn't agree more about getting new drive(s) to take a 
backup before attempting recovery ...

Cheers,
Wol