Re: Add a 3rd drive to a existing raid1 (not as spare)

[Reco <recoverym4n@gmail.com>]

 Hi.

On Tue, Apr 14, 2015 at 11:42:22AM +0200, basti wrote:
> Hello
> I want to add a 3rd drive to a raid 1 array (for disaster backup, the
> drive will be connectet once a week).
> I dry:
> 
> mdadm --add /dev/md1 /dev/sde1
> 
> when I fail the drive there is a message
> 
> FailSpare event detected on md device /dev/md/1, component device /dev/sde1
> 
> How can I add the 3rd drive as "real drive" and not as spare?

You've started going into right direction, but there's one small step
you need to take:

mdadm --add /dev/md1 /dev/sde1
mdadm --grow --raid-devices=3 /dev/md1

Last command will convert spare drive to a 'real' one.


Or, you can play rough:

mdadm --grow --raid-devices=3 --force /dev/md1
mdadm --add /dev/md1 /dev/sde1

Reco