I had previously posted about issues I was having upgrading to FC12 and subsequently discovered that the Fedora installer does not officially support upgrades to degraded RAID systems.

I run a simple two disk RAID1 system. When upgrading, I split the system and run a degraded RAID1 disk for the upgrade. This is a risk mitigation strategy. Should the upgrade fail disastrously I have a backup that I can use for immediate recovery.

If you're lucky enough to have a duplicate system, you can split the RAID1 set and perform the upgrade on the clone while keeping the main system running.

Recent versions of the Fedora installer will not offer an upgrade on a degraded RAID1 system. One workaround is to convert the degraded RAID1 into a singleton.

I think the most straightforward way to do this is:
  • Boot into Rescue Mode
  • mkdir /dsk
  • mount -o ro -t ext3 /dev/sda2 /dsk
  • cp /dsk/etc/mdadm.conf /etc
  • umount /dsk
  • mdadm -A
  • mdadm --grow --force -n 1 /dev/md0
  • Repeat for /dev/md1, etc
Note that I've assumed an ext3 file system on the RAID1 partition (/dev/sda2 in my case).

Reboot into the installer and perform the upgrade.

There is a defect in the boot script which will prevent booting into a singleton RAID1 system. Until fixed, a workaround is to reboot into Rescue Mode after upgrade, and change to a degraded RAID1 system:
  • Boot into Rescue Mode
  • mkdir /dsk
  • mount -o ro -t ext3 /dev/sda2 /dsk
  • cp /dsk/etc/mdadm.conf /etc
  • umount /dsk
  • mdadm -A
  • mdadm --grow -n 2 /dev/md0
  • Repeat for /dev/md1, etc