The server supports one or two M.2 form-factor SATA drives for use as an operating system boot solution. With two M.2 drives configured, the drives are configured by default as a RAID-1 mirrored pair for redundancy.
The M.2 drives install into an M.2 adapter which in turn is installed in a dedicated slot on the system board. See the internal view of the server in the Components and connectors section for the location of the M.2 slot.

There are two M.2 adapters supported:
•Single M.2 Boot Adapter, which supports one M.2 drive; available as ThinkSystem M.2 Enablement Kit, 7Y37A01092
•Dual M.2 Boot Adapter, which supports one or two M.2 drives; available as ThinkSystem M.2 with Mirroring Enablement Kit, 7Y37A01093

Features of the Dual M.2 Boot Adapter:
•PCIe 2.0 x2 host interface (connects to the PCH)
•Based on the Marvell 88SE9230 6 Gbps SATA controller
•Supports two 6 Gbps SATA M.2 drives (it is not supported to have only one drive installed)
•Supports 3 different physical sizes of M.2 drives: 42mm (2242), 60mm (2260) and 80mm (2280)*
•RAID functionality provided by the M.2 adapter
•RAID 1 by default; also supports RAID 0 and JBOD
•UEFI-based settings to enable/disable RAID mode and to review inventory
•Adapter and drive firmware update using Lenovo firmware tools
•Management via I2C interface

* 2242, 2260 and 2280 are the industry terms for the M.2 drive dimensions. For example, 2280 corresponds to a drive that is 22mm wide and 80mm long.