For a moment there it seemed like I would manage it.
I rebooted the NAS and was able to remove original array.
But after trying to create a new one... Well, the problem is the same as when I
first tried to delete the array. It asks confirmation etc, then it timeouts, and
the red error light starts flashing (which it didn't do while trying to delete it).
After a new reboot the original array is back up again.
This can't really be this hard, can it?
Btw, the manual tells me that I have three options regarding the use of RAID.
RAID0, RAID1 and the normal mode, where each HD is considered as an independent
disk, thus allowing the use of the whole 2TB, without the risk of losing everything, if only
one of them breaks down. But while trying desperately to get at least RAID 1 working,
I couldn't figure out how to "turn off" RAID completely.
The manual tells me to create a RAID array after selecting unallocated array, but the GUI only allows me to create a new array after I check both the disks and choose either RAID0 or RAID1 from the drop-down menu.