5 Things to Know About the Synology DS1823xs+ Expansion
Regarding the Synology: 1. Two eSATA ports let you add up to two DX1222 expansion units, each adding 12 bays for a total of 24 extra bays.
The single PCIe 3.0 x8 slot can fit a 10GbE network card or an M.2 SSD adapter, but not both at once.
Expansion units connect via eSATA, which limits bandwidth compared to Thunderbolt or USB-C alternatives.
You cannot daisy-chain expansion units; each DX1222 must connect directly to its own eSATA port.
The 10GbE card is the better upgrade for most users, as it improves network throughput more than M.2 caching in typical home or small office setups.