Re: RAID5 grow interrupted.

[Andreas Klauer <Andreas.Klauer@metamorpher.de>]

On Thu, Sep 22, 2016 at 04:11:28PM +0200, Axel Spallek wrote:
> I tried to get a disk out of a RAID5 with 8 hdds (4TB) to get a Hotspare 
> to change to RAID6 afterwards.

I'm a bit confused here.

You started out with 8 disk RAID-5? And final result is to be what?
RAID-6 with 8 disks?

> Therefore I issued the following commands:
> 
> mdadm --grow -n7 /dev/md1  <-- just to get the size for the next command.
> 
> mdadm --grow /dev/md1 --array-size 23441292288
> 
> mdadm --grow -n7 /dev/md1 --backup-file /var/backups/mdadm.backup

I'm not sure, but you might not have needed any of these intermediate steps. 
But now you started it you might have to finish them.
That said there is a reshape revert (which is not yet in the manpage?) 
which might help if the regular reshape just won't resume.

> root@s10:~# mdadm -A --scan --verbose
> mdadm: looking for devices for further assembly
> mdadm: /dev/sdg1 is busy - skipping

It says busy because already assembled (or in use by something else).
So you have to stop first before assembeling again.

I didn't see anything out of place in your --examine.
It seems to be in sync, event count identical, ....

Good luck
Andreas Klauer