The Synology DS920+ jumps from 4 to 9 bays with one expansion unit

Four internal bays might not sound like much, but Synology designed the DS920+ with a single DX517 expansion port that takes you to 9 bays. That’s more than double the storage without replacing the whole NAS — a smart mid-point between compact 4-bay appliances and the full-sized 8-bay units.