M.2 NAS server

M.2

— a connector for connecting components of a miniature form factor — both drives and expansion cards.

Note that two electrical (logical) interfaces can be implemented through this connector — SATA 3.0 and PCI-Express, and each individual M.2 socket on the board can support both of these interfaces at once, or only one of them. These nuances should be clarified before buying, since the possibilities for using M.2 directly depend on them. So, with support for SATA 3.0, such a connector is intended exclusively for drives, and the speed of SATA is noticeably lower than that of PCI-E; so this M.2 variant is mostly used by inexpensive SSD modules. In turn, PCI-E is somewhat more expensive, but it is faster and more versatile. Support for this interface allows you to connect both high-end SSDs and various expansion cards (for example, sound cards or internal wireless adapters) to the NAS server.

Also note that M.2 was originally used as an auxiliary interface, in addition to SATA 2 or SATA 3 (see the relevant paragraphs). However, NAS servers have appeared relatively recently, where only such connectors are used for drives — these are mainly ultra-thin desktop solutions.