With the new x23 models being delivered, a lot of chat has started up again surrounding the NVMe slots on Synology Diskstations. Until now, the only official way to use these slots was as a read or read/write cache, not always something that was a) desired b) needed or c) actually that useful, given the way an associated volume would crash if the r/w cache failed. A better option (most agreed) would be to use those NVMe SSDs as a separate volume.
The DS923+ has been given that ability right out of the box, and can be set up from DSM. Officially, Synology has not provided support for any older models, but there is a way... and that way is detailed below.