Really the network is the least expensive part. To get IO that can saturate a 10G costs around 20k, while the infiniband card sets you back less than 4k. Now you're talking about 100G, which will go faster, you could easily be looking at a 500k box of ssds.
Wait, what? 10G is 1.2 GByte/s, you can get that from a single SSD easily. 100G is 12 GByte/s, so 5 consumer-level ssds. Squeezing 12 GByte/s over the buses twice might be tricky, but certainly not a 500k problem.
That's 2600 MB/s read speeds. Or more than double your 10G Ethernet.
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RAID0 8 of them together with ASRock's M2. Quad Ultra, and you've got $1040 of SSDs + $200 for the 2x Quad Ultra cards, or just $1200 for 20GB/s read/write speeds. More than enough to saturate any network I'm aware of.
10 gigabit Ethernet is 10 gigabits of data. It's mainly Infinband that used a horrible marketing tactic of saying the signal rate instead of the data rate.
10 gigabit ethernet is not 1 GB/s. It's 10 gigabits of data per second, or 1.25 gigabytes per second. The encoding is not an issue with these data rate numbers because Ethernet quotes their data rate as a data rate.