In K6, I'm observing more fail request in my performance test execution with dial tcp : I/O timeout. Please suggest any fine tuning if I missed at K6.
With low concurrent let’s with 225 users no issues but when increase user to 300 am facing this issue and I'm using MacBook for the test execution
This error indicates that your server under test isn't able to keep up with TCP connection attempts from k6, which is usually a hint that you're reaching the performance limits of what your server is able to deliver.
At this point you would have to tweak your server settings or increase app performance to reach the levels you're aiming for. One sanity check you can do on the server side is confirm if the maximum number of file descriptors (which includes network sockets) is sufficient for your test. See ulimit.