Today's servers utilize controllers to connect storage drives, networks, and other technologies we used to call peripherals. These are often separate add-in cards utilizing PCI-e or other standards, though some server motherboards and chassis may offer built-in choices as well. Built-in controllers are convenient but may offer modest capacities and performance. They also are less readily upgraded to exploit technology improvements.
In this section, we will explore a number of choices for your Ceph servers' controllers.