[CentOS] Problem with mdadm, raid1 and automatically adds any disk to raid

[Jobst Schmalenbach]

On Mon, Feb 25, 2019 at 11:23:12AM +0000, Tony Mountifield (tony at softins.co.uk) wrote:
> In article <20190225050144.GA5984 at button.barrett.com.au>,
> Jobst Schmalenbach <jobst at barrett.com.au> wrote:
> > Hi.
> > CENTOS 7.6.1810, fresh install - use this as a base to create/upgrade new/old machines.
> > 
> > I was trying to setup two disks as a RAID1 array, using these lines
> > 
> >   mdadm --create --verbose /dev/md0 --level=0 --raid-devices=2 /dev/sdb1 /dev/sdc1
> >   mdadm --create --verbose /dev/md1 --level=0 --raid-devices=2 /dev/sdb2 /dev/sdc2
> >   mdadm --create --verbose /dev/md2 --level=0 --raid-devices=2 /dev/sdb3 /dev/sdc3
> > 
> > then I did a lsblk and realized that I used --level=0 instead of --level=1 (spelling mistake)
> 
> So I believe you need to do:
> 
> mdadm --zero-superblock /dev/sdb1
> mdadm --zero-superblock /dev/sdb2
>

I actually deleted the partitions, at first using fdisk than parted (read a few ideas on the internet).
Also from the second try onwards I also changed the partition sizes, filesystems.
Also I tried with one disk missing (either sda or sdb).


Jobst




-- 
If proof denies faith, and uncertainty denies proof, then uncertainty is proof of God's existence.

  | |0| |   Jobst Schmalenbach, General Manager
  | | |0|   Barrett & Sales Essentials
  |0|0|0|   +61 3 9533 0000, POBox 277, Caulfield South, 3162, Australia