x4x4 PCIe to Dual M.2 for 1u Chassis?

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NateR

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Feb 10, 2022
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Hello, all,

I've got a couple SuperMicro 5018-FTN4 servers that I've got fully loaded at this point, and am looking at trying to add a couple of additional SSDs to it. I already have them packed, so there is no room for any additional 2.5in SSDs (I've even designed and 3d printed brackets to stack 2.5in drives on top of the 3.5in drives).

The motherboard in this has a single x8 PCIe slot that supports x4x4 bifurcation. The riser card that is in place will not allow a full low-profile PCIe card, as there is a hard drive in the way.

My question: Are there any PCIe x8 to x4x4 dual-m.2 bifurcation cards on the market that are low-profile enough to fit into a 1u chassis? It would need to have one m.2 slot on one side, one m.2 slot on the other side, and no taller than just a single m.2 drive's width.

The following could be an option, but is a bit on the higher side price-wise, and would need to desolder the top PCIe passthrough slot in order to allow the vertical clearance (and even then, might be a few millimeters too tall): PCIe Bifurcation Card - x8xM.2xM.2 - low Profile Adapter. I also see other single-drive options, but am hoping to put 2x drives in there. Curious if there are any other options on the market.

Thank you
 
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NateR

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Feb 10, 2022
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Way too tall. This needs to be able to fit vertically into a 1u chassis.

I actually just found something that would work... It requires that I use 1x NVMe and 1x SATA SSD. Not quite ideal, but is the best option I have found, as I do have spare SATA ports. If anyone knows of basically exactly this, but support 2x NVMe drives (from an x8 slot, via x4x4 bifurcation), that would be perfect. Otherwise, this would be entirely serviceable: https://www.silverstonetek.com/en/product/info/expansion-cards/ECM28/
 
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mattventura

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Nov 9, 2022
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I see what you mean now. I don't think there's anything out there that perfectly fits the bill. What about getting creative with a flex riser?
 

NateR

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Feb 10, 2022
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I see what you mean now. I don't think there's anything out there that perfectly fits the bill. What about getting creative with a flex riser?
Not really anywhere to relocate the card that it would relocate, unfortunately. I've looked around for some x8 to 2x x4 risers (so that I could then go from each x4 to an m.2 adapter), but between difficulty finding all the needed parts, the added cables further reducing airflow, and the added cost of all the extra pieces, I'd lean toward that 1x SATA + 1x NVMe option over it. I don't need the speed, just would like to avoid using the extra SATA port (just to leave options open later, like if I got crazy enough to run some external drives) and would prefer to only purchase NVMe m.2 drives going forward (as they'd have more use being repurposed in the future), if there are any 2x NVMe options out there.

If there aren't, though, I think that I am satisfied with the SATA + NVMe option.
 

NateR

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Feb 10, 2022
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Yeah, unfortunate. The last thing I can think of would be something like this (https://www.amazon.com/Adapter-SFF-8643-Expansion-Indicator-Windows/dp/B0B7SNH23Y) paired with a dual M.2 carrier (https://www.amazon.com/Xiwai-Express-Slimline-SFF-8654-Adapter/dp/B09YCGZXY1) and appropriate cables, though that might still be slightly too tall.
Thank you for the suggestion. I took a look at that at one point, and the only place that it would fit in there would block all airflow from the hard drives.

Looks like I'll go with that NVMe + SATA option. Thank you for your thoughts on this!
 

NateR

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Feb 10, 2022
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Something like this but for x8 ?

Maybe try it to see what works in your setup ?
Yes, that in x8 is exactly what I am looking for. The x8 slot on this board is closed on the back, and there's a connector right behind it that would block anything longer, so I can't simply cut out the back of it.

EDIT: Just took a look at their other offerings. This is closer, but for some reason they still insist on using an x16 slot: https://www.asrockrack.com/general/productdetail.asp?Model=RB1U2M2_G4#Specifications


EDIT 2: It looks like the 2x drive variant was designed for x8x8 mode, based on the locations of the traces. Also, was just measuring my chassis to see if the 4x drive variant would fit with the risser. Looks like there's just enough clearance between the riser and the hard drives, but the overall length of the card is longer than the chassis is deep (it's about as deep as a network switch, at 10in).
 
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sko

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Jun 11, 2021
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AOC-SMG3-2H8M2-B | Add-on Cards | Accessories | Products - Super Micro Computer, Inc. should be what you are looking for. But this can only support 2280 drives.

But I wonder why you don't use the AOC-SLG3-2M2 carrier. It's a low profile card so it should fit perfectly fine into the 5018 even with LFF drives installed. I'm running several of those carriers in low-profile slots in various supermicro systems and there is usually plenty of wiggle room left.
 

NateR

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Feb 10, 2022
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AOC-SMG3-2H8M2-B | Add-on Cards | Accessories | Products - Super Micro Computer, Inc. should be what you are looking for. But this can only support 2280 drives.

But I wonder why you don't use the AOC-SLG3-2M2 carrier. It's a low profile card so it should fit perfectly fine into the 5018 even with LFF drives installed. I'm running several of those carriers in low-profile slots in various supermicro systems and there is usually plenty of wiggle room left.
Thanks for the suggestion. I've spent some time looking at that and the manual, and I'm fairly certain that's not going to work with a standard PCIe x4 slot. Pretty sure that's proprietary.


As for not fitting... Even without the 2.5in drives on top of the HDDs, it's not going to fit (don't mind the 3d-printed fan bracket - that's coming out and I'm going to come up with something else to cool the HDDs):
1679098021742.jpeg

The HDD comes up about halfway up the PCIe mounting slot in the chassis. It may be possible to fit a card in the riser, but it would have to be one of those 1u-tall-compatible cards anyway... and we're back to the original question, at that point.


Regardless, had this and the extra drive show up today. Going to see whether I can boot from it now (mainly concerned about the NVMe drive - the SATA m.2 shouldn't have an issue): Amazon.com



EDIT: "Great success!" Installed the NVMe drive on that board, disconnected all others, installed TrueNAS, and it booted right up! SuperMicro support had said it would work if you used a PCIe card with an "NVMe controller chip built-in." Not exactly sure what those do, but it worked for me with this and a Samsung MZ-VLW2560 PM961.
 
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zac1

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Oct 1, 2022
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Without sounding snide, have you considered a different chassis? Seems like your requirements have outgrown the 505. I dig the creative shoehorning, though!
 
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BlueFox

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Oct 26, 2015
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Thanks for the suggestion. I've spent some time looking at that and the manual, and I'm fairly certain that's not going to work with a standard PCIe x4 slot. Pretty sure that's proprietary.
AOC-SMG3-2H8M2-B is 100% proprietary indeed. Won't work with anything but a few specific Supermicro systems.
 

NateR

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Feb 10, 2022
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Without sounding snide, have you considered a different chassis? Seems like your requirements have outgrown the 505. I dig the creative shoehorning, though!
Probably not, at this point... Just bought it a few weeks ago, and my vague ideas didn't turn out as I'd thought, so have made a couple of modifications to get everything working how I want. It's going to be a pretty static, long-running server (off-site backup server), so I don't believe I'll want it to grow anywhere beyond this for a very long time.

Technically, the fan and the extra 2 SSDs aren't strictly needed - I could run the VM and the TrueNAS apps off the HDD without any issues, and without the fan the HDDs idled at 50c, well within their operating temperature (just 5c higher than I'd like, though, based on the studies I've seen on temperature-to-failure-rate correlations). I'd drop both those over moving things to a different chassis. But I get "warm fuzzies" whenever I get things set up in exactly the way I want them to work out, and been quite enjoying the challenge of making this happen. All the pieces are in place at this point, just re-designing the fan mount, and it'll be complete.