3 Things to Know About Synology DS220+ Expansion Options
Regarding the Synology: 1. One eSATA port supports a DX517 expansion unit This adds up to five additional drive bays for storage growth.
Two USB 3.0 ports are available for external drives You can connect external hard drives or other USB peripherals directly.
Expansion is limited to a single eSATA connection You cannot daisy-chain multiple expansion units through the eSATA port.