The whole point of a mirrored RAID array is that if one of the drives fails, you should still have a backup of the data on the other drive. That’s not the case with a striped array, which splits the data onto two different drives—unfortunately, that means if one drive fails, the data on both drives is useless, even if one of the drives is still functioning perfectly. A 0+1 configuration should provide a good combination of speed and backup, but you have to be very careful when you’re trying to configure the setup that you don’t mess up the whole configuration when you replace a failed drive within it. If you’ve deleted the whole RAID setup and then started to write over the drives with other data, you may find it hard to recover the data that SHOULD have been safe and sound on the still-intact mirrored pair, unfortunately.