# What Do I Do If a Load Balancer Fails the Stress Test?

1. Check the load of backend servers. If their CPU usage reaches 100%, applications may have performance bottlenecks.
2. Check the incoming traffic. If the incoming traffic exceeds the maximum bandwidth set for the EIP, a large number of packets will be lost and requests will not be responded to, thereby affecting the load balancer's performance.
3. Check the number of short connections in the time_wait state on the clients. A possible cause is that there are insufficient client ports.
4. The listening queue backlog of the backend servers is full. As a result, the backend server does not respond to SYN ACK packets, and the client times out. You can increase the upper limit of the backlog by adjusting the net.core.somaxconn parameter.

Parent topic: Service Performance and Load