Bifurcation on X11SRL-F

[xylcro]

Hey everyone, hope y'all are doing fine today.

I'm in need with some help for my new Unraid build. 

So my new build has a X11SRL-F motherboard paired with a Xeon W-2255 CPU and 128GB of memory. I used my Broadcom 9305-16i from my old server 'cause it still works and there's no need replacing it. I'm also using my Quadro P2200 for transcoding (which is probably overkill but hey).

I decided to purchase an Intel X520-DA2 for that 10G uplink. For cache I currently have 1 x 1TB SSD for downloading stuff, the mover moves everything over to the array daily. Also in there is 1 x 500GB NVMe drive that I use for Docker, VMs and Plex metadata. 

However I want to move both SSDs to a Raid 1, with the normal SSDs this isn't a problem, with the NVMe it is since I only have 1 M.2 on my motherboard. I already have a AOC-SLG3-2M2 M.2 carrier card on the way but I don't really know how the bifurcation would work since I've never done that. As I understand it it splits the PCIe slot into 2. What slot do I need to put this into though, my x16 is occupied by the GPU, can I just plug it in to an empty x8 slot and bifurcate that slot? The manual of the X11SRL-F isn't all too clear on how this works...

Both nvmes would go into the carrier card so the M.2 on the motherboard would stay empty.

 

Thanks for the help.

[JorgeB]

26 minutes ago, xylcro said:

but I don't really know how the bifurcation would work since I've never done that.

You just enable it in the BIOS for the slot you want, I have the similar X11SPL-F and IIRC all CPU PCIe slots support bifurcation.

 

Edit: they are not that similar, different CPU family, check the BIOS for bifurcation support, would still expect it to be supported in that board.

 

 

[xylcro]

2 hours ago, JorgeB said:

You just enable it in the BIOS for the slot you want, I have the similar X11SPL-F and IIRC all CPU PCIe slots support bifurcation.

 

Edit: they are not that similar, different CPU family, check the BIOS for bifurcation support, would still expect it to be supported in that board.

 

 

 

I know it's supported, I'm just unsure about 2 things:

1. which IOU I need to select (see screenshot)

2. What will happen if I choose 4x4x4x4 for example: will the rest of the slots in that IOU also go to x4 mode? I'd like to not do that since that would mean slower speeds for the GPU/10G/HBA

 

 

[JorgeB]

20 minutes ago, xylcro said:

1. which IOU I need to select (see screenshot)

Board manual may show that, but not always, worst case do it by trial and error.

 

21 minutes ago, xylcro said:

What will happen if I choose 4x4x4x4 for example: will the rest of the slots in that IOU also go to x4 mode?

No, they should be per slot.

 

[xylcro]

17 minutes ago, JorgeB said:

Board manual may show that, but not always, worst case do it by trial and error.

 

Maybe the "PEG1" is IOU0 and so on... That's the only thing in the manual I could find. If it isn't that I'll try one by one.

 

Quote

No, they should be per slot.

 

 

This I don't understand, what do you mean "should be per slot"?

 

 

Edited April 16, 2024 by xylcro
Edit: wrong quote + image

[JorgeB]

1 hour ago, xylcro said:

his I don't understand, what do you mean "should be per slot"?

If you enable bifurcation for for example PCIe slot2, only slot2 will use it

[xylcro]

1 minute ago, JorgeB said:

If you enable bifurcation for for example PCIe slot2, only slot2 will use it

 

Ah. That's not possible I think, I can't actually set bifurcation per slot, I have to select an IOU to set bifurcation, and I think that's a group of slots instead of just one.

I'll look again in the BIOS once Unraid is done moving stuff.

[xylcro]

Alright so I have to choose the correct IOU bridge and it's not labeled anywhere as to which bridge goes to which slot. It's going to be trail and error it looks like...

Will update once the carrier card gets here.

Edited April 17, 2024 by xylcro
Typo

[xylcro]

Update: plugged the card in with 2 nvme's and it just worked..... link speed downgraded to x4 for both ssds as it should and the other pcie slot on the same IOU bridge still gets its full x8.

So yeah... I was stressing out for nothing pretty much.

 

Thanks for the help!