I just tried to install Debian on Disks that had been a raid array earlier. The installer recognizes this but delete fails because one of the old arrays was somehow active.
[Solution]
The issue was that a swap partition was a raid1 and the installer did recognize it as such, and use it. To be able to destroy the raids and completely wipe the partition tables in the installer, I had to go to a Shell (Ctrl+Alt+F2) and execute some commands.
!!!!! VERY DESTRUCTIVE - BE CAREFUL !!!!!
Code: Select all
# swapoff /dev/mdx
# mdadm --stop /dev/mdx
You can switch back to the installer with Ctrl+Alt+F1 and then use the GUI to delete the stopped md raid and consequently the used partitions of the mdadm softraid.