>>1. How can I controll during the running system, if BOTH disks are ok? With software-raid I only have to type >>"cat /proc/mdstat". But how do I handle this with hardware-raid? >I'm not sure what you mean. >>2. How do I determine that one disk fails? >From my experience, you'll know if a disk fails.. The system will crash. I mean: How do I know that ONE disk of the RAID1-ARRAY fails??????