The present invention relates to a new design for an extensible architecture for a rack-mounted network attached storage. In one embodiment, the design employs a riser card for a rack-mounted network attached storage. The riser card provides multiple, e.g., four, eight, etc., SATA connections from a PCIe bus on the motherboard. In addition, the riser card may provide power connections and a fan controller. In addition, the riser card supports dual-power inputs from multiple power supply sources. In one embodiment, the riser card can share power from AC power from the rack and a DC input to receive power from an external power supply.