Using two PCIe Cards on one PCIe Bus possible?

[janb14]

Hello folks, i recently got my hands on an
Supermicro Mainboard X10SDV-4C-TLN2F
as my new Freenas box. In the near future i plan to get a IBM M1015 to flash it and extend my usable sataports.
As im doing alot of expiriments with HEVC or h265 i noticed i would like to have a h265 rdy card from nvidia like the gtx1030 in there to hardware assist decoding. But the bord only has one PCIe 3.0 x16 port.
Would it be practical to use an PCIe splitter? Specially as i would rarely, probably never use the graphics card? I know the IBM M1015 only requires x8 lanes so there would be some room to maybe run the gtx 1030 in x8 lane mode ?
What are your thoughts on that?

 

[rvassar]

FreeNAS will not support any kind of GPU use, or pass thru. Sorry.

 

[janb14]

Wait, i can't just slam a GPU in and use ffmpeg inside a vm or jail ?

 

[rvassar]

Wait, i can't just slam a GPU in and use ffmpeg inside a vm or jail ?

No. Not supported, and in all likelihood, not possible.

 

[IceBoosteR]

Never heard of someone who uses two PCIe Cards on just one port. Nevertheless, use hypervisor such as ESXi to passthru the graphicscard to a VM. But please notice, there are some problems know where this is not working with nvidia consumer graphic cards.

 

[pschatz100]

From published specs, the X10SDV-4C-TLN2F does not look like a good choice to set up for video transcoding. Xeon-D processors have very low Passmark performance per CPU. As a file server, it looks OK.

I have been using HEVC and h.265 extensively for over a year. However, I use media player devices that can handle h.265 natively, which means my FreeNAS system and Plex server rarely needs to transcode video. Depending upon the audio format, sometimes the system has to transcode audio, but that is a far smaller task than transcoding video.

 

[Ericloewe]

You can't just split PCIe willy-nilly.

Some motherboards may support that to some extent, but only for specific combinations. And it depends on CPU support.

What is always supported is a PCIe switch. A 32-port switch is probably expensive enough to make you reconsider this endeavor, however.

 

[pro lamer]

Some motherboards may support that to some extent,

@janb14You may look/search for "bifurcation" keyword (e.g. in the mobo manual, forums etc)

EDIT: but I think it would limit you to the half of the PCIe bus width available to the slot. (But don't know if it would be a problem)

X10SDV-4C-TLN2F does not look like a good choice to set up for video transcoding

Noob's question alert: ;) is the decoding phase always done by the means of a CPU?

 

[IceBoosteR]

Noob's question alert: ;) is the decoding phase always done by the means of a CPU?

This depends on the software you are using. Think of Adobe Premiere Pro. Premiere can use the CPU or the GPU or both for rendering your footage. Other tools don't have the feature and uses only the CPU because it is less compley to use for the developer.
It's the same with your transcoding software. It depends if you can use a discrete GPU for that. Same with the crappy Quicksync from Intel.

 

[Stux]

X10-SDV boards do support PCIe bifurcation on their 16x slot. You should be able to use a PCIe splitter like you describe.

But FreeNAS does not do anything with GPUs.

Perhaps with a decent hypervisor you could run an os and pass through the gpu into that....

 

[Ericloewe]

X10-SDV boards do support PCIe bifurcation on their 16x slot.

But do they support x8/x8?

 

[pschatz100]

Noob's question alert: ;) is the decoding phase always done by the means of a CPU?

In the FreeBSD and FreeNAS world, yes. For other operating systems, not necessarily.

But keep in mind:
Decoding is done by the player, not by the server. If the player supports the format of the video file being served when you play a video, then the server only has to "serve" the file. No transcoding or significant CPU processing is needed. If the player does not support the file format, then the server will attempt to "transcode" the file to a format the player will understand. For instance, a late model Roku can play back almost any native h.264 or h.265 video without transcoding, but an iPhone would require the server to transcode the video to a format the iPhone can play. So whether or not one has to transcode a video will depend upon the playback device.

There is far more discussion about this in the Plex forums.

 

[Stux]

But do they support x8/x8?

Yes

 

[Stux]

Yes

https://forums.freenas.org/index.php?threads/nvme-m-2-issues.55912/#post-391849