Cheap Desktop 400GbE Switch MikroTik CRS804-4DDQ-HRM Review

pyrolistical•15 minutes ago

Nic needs pcie5 x16 slot, so on am5, take out your gpu

wrs•about 1 hour ago

I haven’t been directly involved in networking for a while, so it was funny to tune back in and see that now not only is 10Gbps apparently no big deal, they even put it on the management interface!

buckle8017•25 minutes ago

Noting actually says those ports have to be for management.

Most people probably would use them for something else.

avidiax•about 1 hour ago

Is there an actual use for this in a homelab? Isn't 25gbps enough that no SSD will saturate it?

toast0•17 minutes ago

I purchased my SSD based on price and I have a AM4 APU so I'm limited to pci-e 3, but a quick check with crystaldiskmark says I'm hitting about 3.6 GB/s on sequential reads in seq1m q8t1 ... That would saturate 25gbps (assuming you have the right access patterns). seq1m q1t1 does 2.3 GB/s on my system, close enough to 25 gbps.

By my math, pci-e 5.0 should do 4x the throughput, so if you had 4 pci-e ssds you wanted to serve over the network and you had the pci-e lanes, you could saturate 400 gbps.

I'm pretty happy with my little baby network with a handful of 10G and 2.5G ports, and I'm cheap so if I made a big upgrade it'd probably be something used that has more 10g ports plus a 40G I could DAC to the adjacent home server ... but my home servers are barely powerful enough to push 10g anyway.

wtallis•32 minutes ago

Please be careful with units. There are high-end consumer SSDs that will deliver data at 14+GB/s, which is much higher than 25Gb/s.

MarkSweep•about 1 hour ago

The second sentence of the article:

> We have a number of these now and have been running our RDMA network backend for the 8x NVIDIA GB10 cluster for several months now, using one.

I have a friend who uses something similar for his 4 NVIDIA GDX Spark cluster.

avidiax•about 1 hour ago

I see, so only if you are running an AI cluster. And what is it transferring between the nodes? Partial computations?

ericd•about 1 hour ago

Essentially, yes. The DGX Sparks, at 128 gigs for ~$4700 are one of the cheapest ways to get enough high-ish speed memory cobbled together to run one of the more capable open weight models to run at home/for a small biz. This switch lets you combine the memory of 2-4 of them.

hgoel•43 minutes ago

DGX Sparks have 200Gbps interlinks for clustering. Apparently switches are the only practical way to scale such clusters beyond 2 nodes even though each Spark has 2 such ports.

corvad•about 1 hour ago

I mean at lot of what a homelab is experimenting. For example I have an absurd amount of communication 56GbE Mellanox switches but never really saturate it.

iso1631•about 1 hour ago

> While $1100 is not a low number

It really is when you're talking 400G.

OK there's very few ports on this, but in general if you're looking at 400g interfaces. $1100 won't even get you a genuine Arista 400G passive DAC.

Cheap Desktop 400GbE Switch MikroTik CRS804-4DDQ-HRM Review

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