Recommended >1gbe adapter for low-power system?

T

torsionbar28

Good morning folks, question on what is the recommended go-to adapter for 2.5g Ethernet in FreeBSD 14.1? Before you respond, I've searched the forums and not found much. Most of the threads on 2.5gbe are folks talking about how pointless and stupid 2.5gbe is, it's just crippled 10gbe, it's pointless so don't bother. Well, hear me out, I have a specific use case.

I have an embedded system I'm building for a client that requires very low power passively cooled hardware. It also needs slightly more bandwidth than 1gbe can provide. 2.5 gbe is the next logical hop. I know adapters like the Mellanox and Chelsio 10gbe cards are well supported, however I read the spec sheets and these older server adapters all consume ~12 watts or so, which is too much. I've tested them, and they get scorching hot and are unsuitable for my use case. They all seem designed for a rack server with forced-air cooling in an air-conditioned data center.

Here's a Chelsio T520 with an 80mm fan blowing directly at it (on the test bench). The finished product can have no fans, and will be in a hot environment, so notgonnawork.

dev.t5nex.0.temperature: 62

The i225 adapter for 2.5gbe however consumes under 2 watts. Perfect. But the internet says the intel 225 is buggy and should be avoided.

Is there a "recommended" 2.5 gbe adapter here in 2024, for FreeBSD 14.1? (10gbe adapter is also acceptable, but it must only consume 4 watts or less).

Thank you in advance.
 
The i225 is pretty much being succeeded by the i226. Off the top of my head: some (later) versions of the i225 do not seem to have those bugs. Based on the small (form factor) PCs I have seen, newer generations seem to now have a preference for using the i226.

I have no experience with the igc(4) driver, but according to if_igc.c - 14.1-R in base there seems to be support for the i226; so perhaps try a card based on that nic.
 
Erichans said:
The i225 is pretty much being succeeded by the i226. Off the top of my head: some (later) versions of the i225 do not seem to have those bugs. Based on the small (form factor) PCs I have seen, newer generations seem to now have a preference for using the i226.

I have no experience with the igc(4) driver, but according to if_igc.c - 14.1-R in base there seems to be support for the i226; so perhaps try a card based on that nic.
Click to expand...
Thanks, yes I'm successfully using i226 on some Linux machines in the field, it has been stable and without issues. But looking at the 14.1 hardware notes shows only the 225 models as being supported:

www.freebsd.org

FreeBSD 14.1 Hardware Notes

FreeBSD is an operating system used to power modern servers, desktops, and embedded platforms.
www.freebsd.org www.freebsd.org

The igc driver supports the following models:
  • I225-LM
  • I225-V
  • I225-IT
  • I225-K
Click to expand...

According to your link however, the i226 models are indeed enabled in the igc driver in 14.1, so perhaps it's just an omission in the documentation?

I will order an i226-T1 card and give it a try...
 
torsionbar28 said:
[…] I have an embedded system I'm building for a client that requires very low power passively cooled hardware. It also needs slightly more bandwidth than 1gbe can provide. 2.5 gbe is the next logical hop. I know adapters like the Mellanox and Chelsio 10gbe cards are well supported, however I read the spec sheets and these older server adapters all consume ~12 watts or so, which is too much. I've tested them, and they get scorching hot and are unsuitable for my use case. They all seem designed for a rack server with forced-air cooling in an air-conditioned data center.
[…]
The i225 adapter for 2.5gbe however consumes under 2 watts. Perfect. But the internet says the intel 225 is buggy and should be avoided.
Click to expand...

I have two different adapters based on the i225, and they both work without issues (uses theigc(4) driver).
In another box I’ve got a Realtek RTL8125-based 2.5GbE interface. It also works very well (requires the driver net/realtek-re-kmod from ports / packages).

However ― Keep in mind that the power consumption of copper ports (RJ45 connectors) is directly related to the bandwidth. When I configure a 2.5 GbE port down to 1 GbE, the power consumption drops instantly by 0.5 W. And 10 GbE is much worse. And this is even the case when the interface is idle, even if it isn’t configured at all: The power is consumed by the active link (carrier) itself.

This is not the case for fibre ports (e.g. LC multimode connectors). In fact, there are 10 GbE fibre interfaces that consume less power than 2.5 GbE copper interfaces. And of course, fibre has other advantages, like being insensitive to R/F emission, and the cables are usually much thinner and lighter.

So, if your setup doesn’t depend on copper, going for fiber might be an option worth considering. Desktop switches with fibre ports (or SFP+ ports for fibre modules) aren’t that expensive anymore. Just a thought. 10 GbE PCIe cards with fibre support (SFP+) based on the Intel 82599 (ixgbe(4) driver) can be bought for around 40 €.
 
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