In the config file, it will boot with:
ide0: /dev/sdc,media=disk,cyls=8192,heads=16,secs=32,trans=none
ide2: /dev/sdc
It will NOT boot with (i.e., when boot=on is added by qm for a given device):
bootdisk: ide0
ide0: /dev/sdc,media=disk,cyls=8192,heads=16,secs=32,trans=none
ide2: /dev/sdc...