What is the purpose of proxy_read_timeout in nginx?

The proxy_read_timeout directive in nginx is used to set the timeout for proxy connections. When nginx is acting as a proxy server forwarding requests to backend servers, if the backend server does not respond within the specified time, nginx will terminate the connection and return an error.

The default value for this instruction is 60 seconds, and can be adjusted as needed. A shorter timeout allows for faster detection of backend server failures, but may also mistakenly identify delays as failures due to long response times. On the other hand, a longer timeout can tolerate delays in backend server responses, but will increase the wait time for client requests.

It is important to note that the proxy_read_timeout directive only controls the timeout for reading responses, and does not include the time taken to establish a connection with the backend server. If a connection timeout needs to be set, the proxy_connect_timeout directive can be used.