Re: 4-disk RAID6 (non-standard layout) normalise hung, now all disks spare

On 26/06/2021 12:09, Jason Flood wrote:

     Reshape Status : 99% complete
      Delta Devices : -1, (5->4)
         New Layout : left-symmetric

               Name : Universe:0
               UUID : 3eee8746:8a3bf425:afb9b538:daa61b29
             Events : 184255

     Number   Major   Minor   RaidDevice State
        6       8       16        0      active sync   /dev/sdb
        7       8       32        1      active sync   /dev/sdc
        5       8       48        2      active sync   /dev/sdd
        4       8       64        3      active sync   /dev/sde

Phil will know much more about this than me, but I did notice that the 
system thinks there should be FIVE raid drives. Is that an mdadm bug?

That would explain the failure to assemble - it thinks there's a drive 
missing. And while I don't think we've had data-eating trouble, 
reshaping a parity raid has caused quite a lot of grief for people over 
the years ...

However, you're running a recent Ubuntu and mdadm - that should all have 
been fixed by now.

Cheers,
Wol