Test 1: Disk Fail
To fail a disk:
mdadm –manage –set-faulty /dev/md0 /dev/sdc1
sudo mdadm –detail /dev/md0
RAID array continues to work, you are able to read and write as nothing happened.
Replace Faulty Disk
remove disk from array:
sudo mdadm –manage /dev/md0 –remove /dev/sdc1
add disk from array:
sudo mdadm –manage /dev/md0 –add /dev/sdc1
When you modify disk configuration Raid array try to sync to return to a normal state.
Test 2: Brutal Power Off
Remove power from all USB extenal disk, Ubuntu says raid array go on error, … uhm strange, don’t you think?
Reconnect power and raid array continue on faulty state, nothing good, best thing is let Ubuntu do, you need to reboot.
Ubunto do an automatic detect and syncronization, and all back OK.
Next Step is “use this array” or back to Menu Post