1.) No, passthrough means just that the module will not 'occupy' the disks, but pass them through to the bios/ other modules. As far as I understand it it will not allow booting of non-RAID NVMe. disks.
2.) Yes, according to conditions described
3.) Yes, hardware key not present
4.) Yes, according to conditions described for Intel/ 3rd party disks

Modules are the same, but they're controlled by hardware key and possibly by (probably hidden) bios settings, the latter depending on chipset generation.

@lfb6
Thanks. I've spent the time since my last post doing a little RTFM'ing. *SMACKING-MY-OWN-HEAD*: "key" is a freaking hardware dongle only usable on a special mobo header... Ok, I'm slowly catching up to the whole vroc thing.

It seems since my mobo with stock firmware does not support booting nvme at all at least not the M.2 variety I own (neither refind nor grub can see it, and both are dependent on EFI/bios services without additional drivers), and there is no physical VROC key header that I can tell, it appears Supermicro just used the VROC efi modules as a convenience for handling RAID for sSATA and SATA for this older mobo? After modding my firmware to include the "NvmExpressDxe_4.ffs" driver, refind and grub can both see my m.2 nvme just fine, and adding boot entries with efibootmgr work just great and I can direct boot my nvme drive no prob.


So, to add direct RAID boot of nvme m.2's on my mobo, it seems there are 2 approaches:
1) Hack/crack existing VROC efi module to get it "turned on" and do its thing (no other possible way since no hardware "key" header?)
2) Mod my bios to install a new efi RAID driver in addition to the "NvmExpressDxe_4.ffs"

Am I on the right track? If you are aware of anything like either option especially a drop-in nvme raid dxe driver, I'd appreciate pointers in the right direction/resources. I've been digging through various threads, but there are years and years and years of 'em. ;)

Correct so far. RSTe was a marketig thingy for older workstation/ server boards, a feature. Now it's become a marketing gag to allow/ control features for these RAID abilities very granular in bios settings for PCH- see manual for *370 chipsets. Earlier it was clear: If this module is in the bios you can use all it's features, now it's different- see the Dell thread.

So RSTe has the old features all were used to, but they changed the name and you have to pay for the new things you may like. Good thing for MoBo manufacturers/ system seller and for Intel, bad for buyers.

1.) correct, but not such easy possibly
2.) correct, but hard to find, it should work together with bios itself such as you can configure a RAID there and it should have it's own software so that you can monitor your RAID without rebooting to enter bios setup.

3.) Buy an adapter card that has it's own RAID bios/ firmware and 2 to xxx NVMe slots...

4.) Fiddling with older versions of RSTe which had NVMe RAID capability without need for a key. These supported a very limited set of (now possibly outdated) Intel NVMe disks, and afaik noone has tried. But maybe you can find somthing on 4.5/&/7 or 5.x tree. But you'r on your own there.

And other question woulde be:
- Do you want RAID just for speed, meaning RAID 0, then every form of fiddling will be great.
- Do you want RAID for increased safety, then fiddling with backward bios mods would be rather contraproductive.

It is actually scam and fraud not "marketing" and comparable to selling a car with a four cylinder engine you can only use two cylinders of. The Engine Power is only calculated on a theoretical basis.

@lfb6

Please correct if wrong:
So basically Intel took software-raid code from linux kernel (Example: https://git.kernel.org/pub/scm/linux/ker...s/md?h=v5.10.15 ) and ported the code to the preboot efi environment, but instead of creating an nvme-compatible raid driver for EDK2 or whatever (Example: https://github.com/tianocore/edk2/tree/m...i/NvmExpressDxe ), they instead crippled the code to only work with select Intel NVMe's and then included it in previous RSTe versions. Then in 2019 they changed the name from RSTe to VROC and added the "hardware dongle-key" to require extra cash to use even the crippled list of Intel's nvme's, and even more cash to use some 3rd party nvme's but still crippled to only work with specific devices. And now Intel's new "VMD" feature for their latest enterprise processors that work with VROC is basically hardware-accelerated-software-raid? But VROC will still fully function without VMDs on the CPU, so again, it's just a software thing.

If that's more or less correct, then it seems "1) Hack/crack existing VROC efi module..." is not just getting the feature turned on without a mobo header for the hardware key, but to also de-cripple VROC to ignore the whitelist of Intel-approved devices and use any nvme device. The same thing would probably apply to "4.) Fiddling with older versions of RSTe...".

As for "3.)": I've put a considerable amount of work into my box to try and get the maximum capability out of the old hardware. For example, it was waaay too loud when I got it but with a couple more mods I'll have my system running fanless, without sacrificing any drive bays or blocking any slots, and on a tight budget. Since my mobo supports bifurcation, I could install up to 16 nvme m.2's. I'll never do that, but I would definitely try a small bucket of budget nvme's in a RAID0 just to try it out. Same thing goes for the 2nd box I bought at the same time, same mobo and proc's but the smaller pizza box chassis. Emphasis on "tight budget", thus old (but beefy) hardware. I'm attempting to learn/experiment with clusters and the enterprise side of things, so I'll be reconfigurring both boxes quit a bit, adding old GPU(s), etc... But all with old enterprise equipment that's cheap but still beefy enough to be useful. VERY LONG AND RAMBLING STORY SHORT, software-based raid for nvme is plenty good and far more versatile for me so I can't justify the expense of a hardware raid card. Inserting NvmExpressDxe_4.ffs into my bios image solved one big issue, but I still want to try to get bootable raid0.

For completeness, I suppose I have to add another option: "5.) Port md code from linux kernel source to EDK2 for DXE/PEI". This might be a bit outside my realm of possibility at the moment.


So "2.) Mod my bios to install a new efi nvme RAID driver..." seems the only reasonable alternative. Are there any projects/resources/hacks being done on this?


Thanks! You've been a big help as a wrap my noggin around this whole thing.

Intel® Rapid Storage Technology (RST) remapping of PCIe storage devices (HP)
https://h20195.www2.hp.com/v2/GetDocumen...me=4AA7-8270ENW

'Remapping' seems to be the explanation for some 'disappearing' NVMe devices when having RST controller configured as 'RAID' in bios.

Seems that rst and rste do use different modes for creating NVMe RAID- RST seems to remap the drives (even if on PCIe lanes connected directly to the CPU) to the RAID controller of the chipset/ PCH while later RSTe versions (VROC) rely on certain (Xeon?) CPU capabilities for handling NVMe RAID?

C610/X99 chipset/ PCH can- like newer chipsets- be configured to present either as 2822 or 2826 and RST RAID capabilities can be configured/ restricted via bios- link. But that's dependant on PCH device ID, 8D40h can be changed, 8D44h (C612) seems to be fixed on RSTe, 8D47h (X99) seems to be fixed on RST.

Found a spec for RAID layout on disk. RAID DDF Spec 2.0. It's pretty technical, but not tooooo bad...

I would think that the above layout would also be applied to NVMe drives?!?!?

So, aside from PCIe remapping (I didn't know that was a "thing"), what other differences/"gotcha's" do/might exist with a software-RAID implementation on top of NVMe compared to good-ol'-fashioned spinny disks or SATA ssds?

Found a YouTube video with some hints on x4 NVMe RAIDs, apparently, there is a bottleneck limiting the read speed to 8GiB/s:

https://www.youtube.com/watch?v=lzzavO5a4OQ&t=5s

AMD Boards might support x4 NVMe Raid better than Intel ones.

MSI b450 and z370 Boards support NVMe Raids in m.2. Slots, but a second m.2. Slot ith x4 Lanes is rare. Gigabyte Support tells also, CSM must be disabled, but only AORUS ultra and above support bifurcation. Biostar Boards seem not to support Bifurcation, but NVMe RAID also from B550 if two m.2. ports are available.

ASUS has a very good FAQ-Page on Bifurcation Support:
https://www.asus.com/support/FAQ/1037507
ASUS Support shall recommend X399 and X570 and z Chipsets for NVMe RAIDS, but actually all ASUS Boards as listed in this FAQ all support ASUS Hyper Raid Controller and similar in the first PCIe Port.

ASROck supports NVMe RAID in Bios X399 / X570: Advanced -> AMD PBS and set “NVMe RAID mode” to <Enabled >, CSM must be disabled.

Interesting. When I picked up a used 4x M.2 slot PCIE adapter card, it didn't even occur to me that I might have better perf using 2 separate 2 slot cards on my dual xeon mobo (same kinda mobo pcie lane allocation between procs as the psuedo-dual-proc AMD CPU).

That said, finding a dual slot that is actually a dual M-key and not a hacked up M-key plus B-key sata is surprisingly challenging... It is bizarre how many "single M plus single B" variations there are and so few true dual M.2 NVMe compatible adapter cards. One of the only dual slot adapters I've found that I might buy at some point is the supermicro AOC-SLG3-2M2. But since it costs around $50 which isn't bad for a Supermicro name-brand card, and I can get 4x slot adapters around $75ish, or a single slot adapter for $6... Well, so far I figure either pay $6 for a cheapie adapter OR get a 4 slot ASUS card. I have both and haven't had any problems.

I'm still hoping someone will release an open source EFI driver for at least read-only RAID support for bootable NVMe arrays. The driver would not need to create or maintain arrays, but be barely functional enough to scan and read the RAID metadata from disk and understand the data layout barely enough to get the kernels loaded and leave it to the OS drivers to handle the rest.

You can search for Motherboards with multiple m.2. slots here:
https://geizhals.de/?cat=mbxeon&xf=11924_2%7E8405_GEN34X4
Geizhals has the best metadata of all portals. You just have to find a mobo and look into its manual afterwards in order to find out whether it supports NVMe Raid. In brief, ASUS does best support ASUS Hyper RAIDS, Gigabyte does not offer Bifurcation but if the mobos have multiple m.2. ports then they can also be in a NVMe RAID, Biostar and MSI as well. ASRock offers this feature only with X399 and X570 Chipsets.

Well, I tried out lots of Mainboards now. AMD Chipsets will most likely support NVMe RAID with the AMD Driver from the Homepage if there are at least two m2 slots on board: AMD RAID Driver (SATA, NVMe RAID)
https://www.amd.com/de/support/chipsets/amd-socket-am4/b450

You can use any port, either m.2. directly connected to the CPU or connected to the Chipset via an adapter PCIex4 Adapter Card. I got problems with the ASUS Hyper Card though. It did not work well with the AMD RAID configuration file in the driver, so I could not install windows. I still use an ASUS Mainboard, one m2 in the Slot another in the Adapter Card.

The info on m2 slots was from the Gigabyte support. They say if there are multiple on-board M.2 slots on an Intel Mainboard, then you can build a RAID. Indeed I could using the Gigabyte AORUS B550 Elite AX V2. Anybody wants it? I switched to ASUS now. I guess Gigabyte BIOS supplies the PCIe "Remapping" only for those boards having multiple m2 slots. If there is only one slot, then I could not add the NVME to an Array on an Intel Board. Anyway, AMD NVMe is functional now, only Intel Chipsets make problems because they want to promote Optane Technology. I think you can even combine SATA SSD in an m.2. Slot with NVMe SSD which actually does not make sense, but it seems to be possible. And ASUS does not support NVMe RAID officially, except if you use the Windows install driver from the AMD Homepage. It seems you can build Raids with NVMe and SATA combined when in the m.2. slot. But once you have built an NVMe RAID you cannot use the second m.2 slot for SATA nor the SATA ports 5&6. You have to connect the Sata SSD with a cable to a SATA port then. You can neither build a SATA RAID additionally to NVMe RAIDs. If you want SATA RAID additionally for Data you have to switch the Sata Controller to AHCI and configure a software RAID with "Dynamic Stripped Volumes" within Windows. Performance is great also, even better for small files.

Benchmarks:
NVMe RAID on B450m Mainboard
SATA RAID 2x 128GB Samsung CM871a
Single 5TB HDD WD50EFRX

Now we just have to find out what makes the difference in the BIOS. TUF B450m Plus seems not to be RAID capable, but TUF B450m PRO seems. Same is valid for Gigabyte z370 hd3 vs. z370 hd3p.