M.2 is a solid-state drive (SSD) form factor primarily used as an operating system boot solution. Lenovo ThinkSystem servers support M.2 drives either with the addition of a upported M.2 adapter or directly on the system board.On the ThinkSystem SR150. SR250 and ST250. a single M.2 drive is installed directly on the system board.On all other support ThinkSystem servers. the M.2 drives install into an M.2 adapter which in turn is installed in a dedicated slot on the system board of the server. With two M.2 drives configured. the drives are configured by default as a RAID-1 mirrored pair for redundancy.- Single M.2 Adapter. which supports one M.2 drive; available as the ThinkSystem M.2 Enablement Kit- Dual M.2 Adapter. which supports one or two M.2 drives; available as the ThinkSystem M.2 with Mirroring Enablement KitA Dual M.2 Adapter with one 128GB M.2 drive partially inserted is shown in the following figure. The second M.2 drive is installed on the other side of the adapter.