iperf maxed out at 936 Mbps (117 MB/s). Need help tuning it further.

E

einthusan

I have tried tuning the network card for several weeks and the most I was able to get was 117 MB/s (936 Mbps). The maximum should be 1000 Mbps (125 MB/s). Yes the difference is just 8 MB/s but thats a potential 20 TB over 1 month.
Code: 
8 (MB/sec) * 3600 (sec/hr) * 24 (hr/day) * 30 (days/month) = 20,736,000 (MB/month) = 20 TB/month
Can anyone please help me tune the network card? The maximum reported by others thus far is 117 MB/s, is it even possible to reach 125 MB/s over 1 Gigabit NIC?
 
Actually, I found this thread where two people have claimed to hit 125 MB/s for some time.
http://forums.whirlpool.net.au/archive/1667275

Both of them are using Apple xServe. One of them even posted a graph.

macosx10622010032516493.png
 
Chances are that you get some packet loss at those speeds are high. I personally reach about 109MB/s when transferring files between my workstation and server via a switch and 2.5m of cable. But I am not sure if it is the hard disks fault or not as I have not done any testing.

I'm curious though, whats your packet loss rate?

BTW, more info is always a plus. NIC name, cable length and category as well as any switches the data is passes through.

NB! I am no expert.
 
How can I check the packet loss? I am with a dedicated server provider so I am not sure about the details. However I am testing between servers in the same datacenter. It's an Intel NIC, not sure of the model but it's an "enterprise" level NIC and very good. I think it's an OS/NIC tuning issue more than a hardware problem.
 
Thanks guys. netstat shows no packet drops either so that's good. There is so much misguiding information out there regarding 1 GbE max throughput. Thanks for clearing it up with the wiki page.
 
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