I have very big problem with one of my servers, look like problem is related to ext4 partitions, I have them on all my hard drives...
On this server many times OS start this processes:
they have high cpu usage few seconds but that is not main problem, when this processes running ALL what need hard drives is locked, mysql can`t read/write data from hard drives and in that few seconds I have hundreds queries waiting for execution...and because of this problem I have SERVER BUSY errors for all my visitors!!!
This is very big problem and I don`t know how to fix it!
Some server info:
Linux NAME 2.6.32-358.23.2.el6.x86_64 #1 SMP Sat Sep 14 05:32:37 EDT 2013 x86_64 x86_64 x86_64 GNU/Linux