Acceptor::readCallback fatal errors

[Mis1eader-dev]

A backend running on Drogon for 19 hours started not responding to any requests, checking the console logs I can see this:

20240827 13:14:10.048660 UTC 93159 FATAL Too many open files (errno=24) Accpetor::readCallback - Acceptor.cc:86

Reading the code of Acceptor, it seems it is unable to read from the socket?

After restarting the Drogon backend, it went back to normal.

[an-tao]

This shows that the number of concurrency exceeds the upper limit of open file descriptors for the process. You should increase this upper limit via kernel parameters etc.

[Mis1eader-dev]

Thank you for the explanation, shall we have this as an FAQ?