tl;dr I’m stuck on old dell r720 and I have U.2 NVMe-s collecting dust.
I’ve found a way to connect them to the system without spending too much money.
Here’s a short howto. you can probably adapt it to other old servers if they have enough free space and you’ll find a free header with 12V.
If you want to do it you’ll need 4 things:
- PCIe switch card (old servers don’t support bifurcation)
- SFF 8643 (mini sas hd) to SFF-8639 (u.2) cable (80 cm)
- dell backplane power cable (0123W8)
- some U.2 device
- sacrificial sata extender/splitter
backplane power connectors on dell r720 motherboard:
On this photo cable is already connected. My cable is correctly color coded. Yellow is 12v, black is ground. I haven’t checked gray but some people online claim it’s for backplane sensing.
You have to make solder 12v and ground cables from backplane power to your sata splitter.
My cable
I’ve connected 2 yellow and 2 ground cable to my sata cable just in case. I’ve also later soldered both sata ground cables together, just in case.
This cable has only 12v power but it should be enough for server U.2 drive. You may have problem if you tried to use it with M.2 to U.2 adapters. M.2 drives usually prefer lower voltages (they lack internal power conversion?).
My r720 has only one 8 drive front cage. I’m placing my drives in drive cage blank.
I’ve tested 2 and 4 drive configurations:
2 drives (2 port PCIe switch card)
4 drives (8 port PCIe switch card)
I managed to fit all cables in cable management hole but it’s really tight.
Drives I’ve used:
Intel optane 900P
Samsung PM9A3
Micron 7300 PRO
\o/
All drives are detected and connected at full speed supported by PCIe switch.
Maybe I was lucky with drive selection. I have dead U.2 intel p3600 which requires 0,1A of 3.3v. I couldn’t test it. I’m guessing that future of serverland is in 12v.
If you drive needs 5v you can steal if from loose sata power cable around cd drive. (my server has one). If you need 3.3v you may be able to get it from gray cables on backplane power cable. Or form the other backplane cable.
PCIe switch chip cards used.
Linkreal 2 port card (pcie slot x8)
Ceacent 8 port (pcie slot x16)
Last time I’ve checked Ceacent had much better prices. Silicon is the same both vendors use PLX chips.
https://aliexpress.com/item/4000547648654.html
I’ve also considered cutting front of the empty drive cage blank, drilling few holes for screws and installing IcyDock ToughArmor MB699VP-B… but it costs 380 Euro. That’s insane.
RIP, my pinecil died during this project. It’s the second time I’ve soldered sth with it. (hopefully just the tip is dead)