3 Things to Know About the Synology DS1621+ Drive Setup
Regarding the Synology: 1. Primary storage uses SATA drives The DS1621+ accepts 3.5-inch and 2.5-inch SATA drives, including both HDDs and SSDs, for your main data storage.
NVMe slots are for caching only The two M.2 NVMe slots cannot be used as primary storage volumes. They are strictly for caching to speed up access to frequently used data.
The separation is intentional The DS1621+ keeps a clear divide between storage drives and cache drives. Do not expect to use NVMe drives as main storage.