Well, at last I’m getting somewhere with my troubles. This only seems to be happening when creating an RAID5 multiple device with four disks, this doesn’t happen with three.
Now, the next thing I tried was to create a three disk array, and then adding the fourth disk as spare and then extending the array with that fourth disk. After that, all these errors seem to appear again *yuck* So I either possess rather faulty disks, or something else is fishy, since I’m having another four disk RAID5 array with the old disks …