Azure cloud service network bandwith

Question

I have an Azure web role on 3 Standard_A3s. The web api has a heavy load and it transfers lot of large objects. I am trying to find out at what RPS we might hit network bandwith limit. Is there a way to find this out.

Answer 1

Maximum network bandwidth is the maximum aggregated bandwidth allocated and assigned per VM type. The maximum bandwidth provides guidance for selecting the right VM type to ensure adequate network capacity is available. When moving between Low, Moderate, High and Very High, the throughput will increase accordingly. Actual network performance will depend on many factors including network and application loads, and application network settings.

One user used iPerf to try to get a feel for the network performance between two instances of the same size. Here are his results about network bandwidth: DS1 = ~741 Mbps DS2=~1.5 Gbps DS3-DS5 = ~2.8 Gbps DS11=1.5 Gbps DS12=~2.6 Gbps DS13-15 = ~2.8 Gbps

There definitely seems to me 3 levels, but they don't seem to match what is advertised. It looks like some VMs advertised as "High" are getting speeds comparable to "extremely high". There might have been a performance increase that just has not been documented yet. And of course they don't actually advertised these speeds since the network is shared and your results may vary, but at least you have a general idea of what to expect. Moderate ~750 Mbps High ~1.5 Gbps Extremely High ~ 3 Gbps

Answer 2

According to the Azure documentation, a Standard A3 VM has a max of 2 NICs with high network bandwidth. The problem is that beside the "low/moderate/high/very high/extremely high" values, Microsoft does not provide concrete numbers for network bandwidth. Well, I haven't found them if they exist however, you'll find many blog posts around where people have published their own benchmarks.