I've seen a lot of post regarding how to setup/recover a mirror drive. It seems not much article mention about how to identify a failure drive.

Here are what I want to know if they are healthy:

1. If I've setup a hardware mirror on a general motherboard's built-in RAID controller. (Assuming the computer never power down, so, no BIOS screen could be accessed. And, no special LED on the hard drive that indicate the problem)

2. If I've setup a software mirror thru Ubuntu. How do I know problem exist?

Could I setup some kinds of alert (i.e. send an email to Admin through a script) if they're having problem?

Thanks!