mdadm is not able to create a RAID6 with 3 disks in degraded mode

  • Document ID:3132542
  • Creation Date:14-Jan-2008
  • Modified Date:27-Apr-2012
    • Micro Focus Products:
      Open Enterprise Server
    • SUSE Products:
      SUSE Linux Enterprise Desktop
      SUSE Linux Enterprise Server

Environment

Novell SUSE Linux Enterprise Server 10
Novell Open Enterprise Server 2 (OES2)
Novell SUSE Linux Enterprise Desktop 10

Situation

You are trying to use the following command
mdadm --create /dev/md0 --level=6 --chunk=128 --raid-devices=4 disk1 disk2 disk3 missing
to create a RAID6 with 3 disks. The command exits with the following error messages
ERROR:
mdadm: RUN_ARRAY failed: Input/output error
mdadm: stopped /dev/md0

Resolution

The problem is reported to engineering and update for mdadm will be published as soon as fixed.

Workaround

First create a RAID6 with 2 disks
mdadm --create /dev/md0 --level=6 --chunk=128 --raid-devices=4 disk1 disk2 missing missing
and then add the 3rd disk
mdadm /dev/md0 --manage -a disk3

Status

Reported to Engineering