Recently, at Percona Live Europe 2019, Dimitri Kravchuk from Oracle mentioned that he observed some unclear drop in performance for MySQL on an ext4 filesystem with the latest Linux kernels. I decided to check this case out on my side and found out that indeed, starting from linux kernel 4.9, there are some cases with [&]

https://www.percona.com/blog/2019/11/12/watch-out-for-disk-i-o-performance-issues-when-running-ext4/