I've recently purchased a Gigabyte MZ72-HBO mobo and there are two U.2 NVMe (#38 & #39 on the board diagram in the user manual) ports attached to the CPU0.
Rather naively, I assumed this meant that I could connect a SlimSAS to MiniSAS cable and run the Icy Dock MB720M2K-B 4x M.2 NVMe cage out of these ports (2 slots out of 4 of course, with the remaining slots connecting to the remaining mobo slimSAS ports).
As it turns out, the U.2 and M.2 standards are not just physical connectors but also incidentally pin configurations! Which of course they are (duuuhhhh!) and I had no idea they differed so drastically.
So, IcyDock have advised using some kind of AOC with MiniSAS (SFF 8643) connectors. Cool, seems fair enough.
My confusion has arisen from the amount of lanes, throughput, compatability, and vast array of HBAs available.
So far I've worked out that I need the following:
- 16 PCIe lanes (4 lanes per m.2 drive)
- 16 ports (and that ports/lanes are diff, but incidentally correspond)
- PCIe 4.0
The closest I can find is the following card from Broadcom:
However it's PCIe x8 and has 8654 connectors. Can I run two 8654 which split into 2x each 8643 cables to the cage? Would I need two of a similar card with perhaps 8 ports instead of 16 due to the PCIe lane bottleneck? (Seems a waste as I'll essentially lose 8 lanes on one of the slots) Will I be limited in terms of throughput and will the pins even provide compatability?
It's all very confusing. As it should be.
Finally, the only reason I want this cage is for the obvious: live hot swap of drives in the event of failure. Do these HBA cards facilitate that kind of functionality?
EDIT:
Having spent some time thinking about this solution, it seems rather silly.
Instead of trying to fit a square peg in a round hole, I will simply return the M.2 hotswap cage and use the M.2 drives as-is via an existing pair of PCIe cards.
Upon making further upgrades, I will simply purchase a series of U.2 drives with the appropriate hot swap cage and chock this up to a learning experience.
Rather naively, I assumed this meant that I could connect a SlimSAS to MiniSAS cable and run the Icy Dock MB720M2K-B 4x M.2 NVMe cage out of these ports (2 slots out of 4 of course, with the remaining slots connecting to the remaining mobo slimSAS ports).
As it turns out, the U.2 and M.2 standards are not just physical connectors but also incidentally pin configurations! Which of course they are (duuuhhhh!) and I had no idea they differed so drastically.
So, IcyDock have advised using some kind of AOC with MiniSAS (SFF 8643) connectors. Cool, seems fair enough.
My confusion has arisen from the amount of lanes, throughput, compatability, and vast array of HBAs available.
So far I've worked out that I need the following:
- 16 PCIe lanes (4 lanes per m.2 drive)
- 16 ports (and that ports/lanes are diff, but incidentally correspond)
- PCIe 4.0
The closest I can find is the following card from Broadcom:
However it's PCIe x8 and has 8654 connectors. Can I run two 8654 which split into 2x each 8643 cables to the cage? Would I need two of a similar card with perhaps 8 ports instead of 16 due to the PCIe lane bottleneck? (Seems a waste as I'll essentially lose 8 lanes on one of the slots) Will I be limited in terms of throughput and will the pins even provide compatability?
It's all very confusing. As it should be.
Finally, the only reason I want this cage is for the obvious: live hot swap of drives in the event of failure. Do these HBA cards facilitate that kind of functionality?
EDIT:
Having spent some time thinking about this solution, it seems rather silly.
Instead of trying to fit a square peg in a round hole, I will simply return the M.2 hotswap cage and use the M.2 drives as-is via an existing pair of PCIe cards.
Upon making further upgrades, I will simply purchase a series of U.2 drives with the appropriate hot swap cage and chock this up to a learning experience.
Last edited: