If like me, you manage your own Linux servers, it is essential to know how to release its cached memory. In a nutshell, Linux always tries to use RAM to speed up disk operations. It uses available memory for buffers (file system metadata) and cache (pages with actual contents of files or block devices). This helps the system to run faster because disk information is already in memory which saves I/O operations. If space is needed by programs or applications like MySQL, Linux will free the buffers and cache to provide memory where it is needed.