MySQL errno: 24 - Too many open files

Question

MySQL 5.7.36-39-log Percona Server

Have recently received: errno: 24 - Too many open files

I have observed that status open_files is continually increasing. This is new behavior as the number of open_files used to fluctuate up and down on a daily basis, but it did not continually increase.

Very concerned as it would seem that MySQL is not releasing its hold on files. I will eventually hit mysql/system limits. Not sure what exactly is going on here.

Answer 1

I assume you are referring to Open_files (with a capital O).

Some operating systems set open_files_limit to 1024. This is unreasonably low for MySQL. See ulimit for how to increase it, then restart MySQL.

Don't worry about the STATUS value growing, it seems to have no impact on performance.