Socket Exception while running load test with Self Provisioned test rig - visual-studio

Question

I am getting the Socket Exception while running load test on self-provisioned test rig.
I am trigger those load tests in agent machine(self-provisioned test rig) from my local machine.
Note : For first 2 to 3 minutes test iterations are passing , after that we are getting the Socket Exception.
Below is the error message :
A connection attempt failed because the connected party did not
properly respond after a period of time, or established connection
failed because connected host has failed to respond.
Below are the stack trace details :
at System.Net.Sockets.Socket.EndConnect(IAsyncResult asyncResult) at
System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure,
Socket s4, Socket s6, Socket& socket, IPAddress& address,
ConnectSocketState state, IAsyncResult asyncResult, Exception&
exception)
Run Time - 20min
Sample rate - 10sec
warm up duration 10sec
number of agents used - 2
Load pattern :
initial load - 10user
max user count - 300
step duration - 10sec
step user count - 10
Although, by Changing above values I am still getting the exception in the same way.
I am using Visual studio 2015 enterprise.

Answer 1

The question states: start with 10 users, every 10 seconds add 10 users to a maximum of 300. Thus after 29 increments there will be 300 users and that will take 29*10 seconds which is 4m50s. The test will thus (attempt to) run with the maximum load of 300 users for the remaining 15m10s.
Given that all tests pass for the first 2 or 3 minutes plus the the error message, that suggests that you are overloading some part of the network. It might be the agents, it might be the servers or it might be on the connections between them. Some network components have a maximum number of active connections and the 300 users might be too many.
Increasing the load so rapidly means you do not clearly know what the limiting value. The sampling rate (at 10 seconds) seems high. At each sampling interval a lot of data is transferred (i.e. the sample data) and that can swamp parts of the network. You should look at the network counters for the agents and controller, also the servers if available.
I recommend changing the load test steps to add 10 users every 30 seconds, so it takes about 15 minutes to reach 300 users. It may also be worth reducing the sample rate to every 20 seconds.