Testing RAID Mirror


I have 2 usb drives mirroring each other, how do I test that they are working properly? Also, I accidentally started without one drive powered on, now it is trying to rebuild the mirror, and it is taking forever, is this normal?

On a separate question, I recently ran YASU (cleans up log files, and optimizes os x) and now when I reboot, it asks for my system password, but none of my passwords work, if I press cancel, it does not seem to effect the system, but it is getting annoying. Thanks

Kyle Dibble