Input-output performance problems are on every day agenda for DBAs since databases exist. In Linux - probably the most popular operating system for databases now - there is a major overhaul of the IO stack for last several years. In this talk i will review what is going on there, why the IO stack needed an urgent improvement and what all those brand new NVMe driver and blk-mq layer improvements mean for databases, and database people. As a useful takeaway, I will provide a checklist of PostgreSQL and Linux settings to maximize IO performance with the new kernels.