M.2 riser for LSI controller?

[Richj]

I've been running TrueNAS-SCALE-21.04 for a bit now and core before that, for a month or so. I plan on sticking with SCALE for the foreseeable future. I hope. ;-)

This will be mostly used for typical NAS storage of home dirs, photos, home videos and Plex serving family and friends. Max users would be 8-9 with 5-6 transcodes at a time (NOT from 4k at this time) ;-)

Anyway... I have the following and will need more SATA ports pretty soon.

ASRock X5700M PRO4
AMD Ryzen 7 3700X
64GB DDR4 ECC (4x 16GB sticks)
Nvidia Quadro P600 (for plex transcoding hopefully in the not to distant future)
Intel X540-T2 10Gb NIC

I have a 1TB NVMe for download and transcoding space in one of the m.2 slots. (not protected because I don't care if I lose it)
120GB SSD in an external USB 3.1 gen2 case for boot drive (unprotected but will be saving config off to another system)
2x 1TB SSDs mirrored for appdata (VMs and applications)
6x 4TB spinners for data

With current disk prices I just can't justify installing larger HDs and expanding the datapool AND I'm out of onboard SATA ports. I have the NIC in one of the PCIe 4.0 x16 slots and the P600 in the other. This leaves me with one PCIe 4.0 x1 slot free and the other m.2 slot free. I ran across this and wondered if it might solve my issue of needing more SATA ports. m.2 riser Would this work for for say an LSI 9207 (or similar) to give me more SATA ports? Is it recommended to do this? Is there a better solution?

I could/would drop the 10Gb NIC but my primary NAS currently is a QNAP with 10Gb and I do move a lot of data at times. Once in more familiar with SCALE, and it's out of ALPHA, I'd like to make SCALE my primary and just use the QNAP for backups.

Thoughts, suggestions?

TIA

 

[Constantin]

Wonder if your case could handle a riser card like the Supermicro RSC-R2UT-2E8R 2-Port Riser. Ditto your motherboard - i.e. does it allow bifurcation.

Doubt that either the NIC nor the LSI would ever approach the speeds of the PCI 3.0x8 levels this stuff would likely operate at.

 

[Richj]

That looks like a better solution if I have room. I'll have to get some measurements tonight. Thank you!

 

[Etorix]

The riser should work.
ADT-Link makes all sorts of PCIe risers and adapters, and you can order directly from them with a custom cable length which may not be offered through Amazon. They ship fast from Taiwan. However, if you go this road, do take the time to carefully consider your case, how you're going to route the flat cable and how long it should exactly be: The cable is thick, definitely feels like a quality item but does not lend itself to sharp turns—and should not be folded. Too short is obviously not good, but too long can get cumbersome. Get the right size, and the right geometry at the PCIe slot (left, right or middle).

Doubt that either the NIC nor the LSI would ever approach the speeds of the PCI 3.0x8 levels this stuff would likely operate at.

PCIe4.0x4 has the same bandwidth as PCIe3.0x8, but can it "expand" to present it? I think that with a PCIe3.0 device a PCIe4.0x4 link simply degrades to PCIe3.0x4. That's enough for a single 10 GbE link at full speed or some extra SATA drives tough.

 

[Richj]

This riser option is much better than the m.2 option I found!

Thank you Both!

 

[Constantin]

PCIe4.0x4 has the same bandwidth as PCIe3.0x8, but can it "expand" to present it? I think that with a PCIe3.0 device a PCIe4.0x4 link simply degrades to PCIe3.0x4. That's enough for a single 10 GbE link at full speed or some extra SATA drives tough.

The Intel NIC referenced by the OP is a PCIe3.0x8 card. Therefore, it will never work faster than that. Ditto any 9207-based HBA. The interface simply slows down to the fastest common denominator between the motherboard and the PCIe card. So when the motherboard encounters a non-PCIe 4.0 card, it will simply throttle its interface down 3.0 or lower. No such thing as "expanding" a faster bus to a slower bus + more lanes, to my knowledge. At the very least, that step would require some sort of specialized chip on the bifurcation board, which would increase its cost significantly.

Anyhow, a riser card will make better use of the x16 card slot, which otherwise would have had 8 unused PCIe lanes (the other 8 being used by the Intel NIC at 3.0x8).

However, double-check to ensure whether the motherboard / BIOS supports bifurcation or not. Many boards do, sometimes they need a BIOS upgrade to get there. You certainly do not want to go through the trouble of fitting a PCIe bus bifurcation board only to discover that the motherboard / BIOS does not support bifurcation.

 

[Richj]

The X570M Pro4 supports bifurcation of the primary (x16) slot. I don't have room for a riser "card" but could use one of the cable types in my case. The above ADT-link above doesn't appear to have any dual (x16 to dual x8) style but I'll keep digging. Good info and now I'm going in a more confident direction! Thanks!