Supermicro X12SPM-LN4F : questions about the 4x NVMe port PCI-E 4.0 x4 via SlimSAS

[rcstevensonaz]

[Edit 27-Oct-2023: I don't have sufficient privileges to reply to my own thread. But, quite belatedly, I want to extend a huge thanks to Etorix!!! In hindsight, the explanation is obvious (as is often the case)... but the lightbulb only turned on after reading their well written explanation.]

I am planning to upgrade my home NAS server to a Supermicro X12SPM-LNF4 which provides 2 SuperDOM SATA + 1 M.2 NVMe SSD + 8 SATA ports + 16 additional SAS/SATA ports ("4x NVMe port PCI-E 4.0 x4 via SlimSAS connector").

However, there seems to be very little information about the motherboard's "4x NVMe port PCI-E 4.0 x4" functionality. So I hope others on this forum can help with a few questions:

1. What chipset is used to implement the 4x NMVe port PCI-E 4.0 functionality on the motherboard?
2. Is the chipset supported, or are there drivers that still are missing or incomplete?
3. Does the motherboard ship with it already in "IT" mode (so that it functions as an HBA), or will I need to flash new firmware to shift from Raid (IR) to HBA (IT) mode?

Of course, please let me know if there are any other issues or concerns with this motherboard as well.

Thanks.

 

[Etorix]

"SlimSAS" refers to the connector, NOT to the protocols (SATA/SAS/PCIe) which may be carried through it.

In this case (or rather on this board) there are two orange, SATADOM-enabled, SATA ports, and eight more SATA ports (from the C621A) chipset are available from two SAS-style connectors on the edge of the motherboard, close to the blue USB header, using breakout cables.
Between the chipset and the RAM slots are two white connectors: These are two x8 "SlimSAS" connectors exposing a total of 16 PCIe 4.0 lanes from the CPU. With suitable breakout cables, these could provide four PCIe 4.0 x4 links for four NVMe drives (typically U.2/U.3). No SAS/SATA: The CPU does not support that.

Specification:

• 4x NVMe port PCI-E 4.0 x4 via SlimSAS connector
• Intel® C621A controller for 10 SATA3 (6 Gbps) ports; RAID 0,1,5,10

There is no SAS on this motherboard, and only 10 SATA. If you need SAS and/or more ports, add a HBA in a PCIe slot.