XXXXXXX - PERC6I INTERNAL CONTROLLER FOR 8X HDD CH

PERC6I INTERNAL CONTROLLER FOR 8X HDD CH

Hello, we want to add two new drives to our existing productive Server system

1 X Raid 1    ( 2 x Drives)

1 X Raid 5    (3 x Drives)  

Are we able to safely extend the existing raid 5?   Or is it better to add a another mirror (raid 1)