Azure VM Monitor - Outbound flows and netstat

Question

In the Azure portal I can click at Montoring and change CPU metrics for Inbound or Outbound flows. I can see numbers about 1000. I have time span 30 minutes.

What is the aggregation? Per 1 minute ?

And how are these numbers connected with currently estabilished connections ?
I ran
netstat | grep ESTABLISHED | wc -l

and got currently 256 rows - estabilished connections.

Thanks
Jan.

Answer 1

Hello The sampling depends on the metrics. It should be every 1 minute, unless specified in the metric description, such as reference here for virtual machines. That said if you want to check the sampling frequency, you can select the relevant counter, select the aggregation of count, change the metrics to 30 minutes and the granularity on the chart is set to 1 minute. Then when you highlight the series, just divide the count by 60 seconds to get the answer. Here for Virtual machine Percentage CPU, you can see a count of 4, meaning every 15 seconds (60 / 4).

With regards to the inbound and outbound flows, they show the number of current flows in the selected direction. Your Netstat query will show established connections for the TCP protocol, inbound and outbound flows. A flow is not necessarily the same as an established connection. An established connection is a specific state of a network communication between two endpoints using the TCP protocol. A flow, on the other hand, can refer to any network communication between two endpoints, regardless of the protocol or state of the communication. I hope this clarify things Alistair