Increase the maximum number of open files / file descriptors

Answer:

If you are root, execute the command below

ulimit -SHn 65535

If you want to set it permanently, especially for a particular user, change the file /etc/security/limits.conf to have the following lines (assume user = www-data)

E.g.

www-data hard nofile 65535
www-data soft nofile 65535

And make sure uncomment pam_limits.so from the different files under /etc/pam.d, e.g. sudo, login, sshd, ...

Finally restart your system.

Related posts:

1. How to determine the type of a file in Linux
2. Find files by owner
3. Change the maximum allowed binary log file size in MySQL
4. How to split a large file into multiple smaller files in Linux
5. How to check failed login attempt in Ubuntu