The I/O Scheduler is an interesting subject; it’s something that’s rarely thought about unless you are trying to get the best performance out of your Linux systems. Before going too deep into how to change the I/O scheduler, let’s take a moment to better familiarize ourselves with what I/O schedulers provide.
Check your current I/O Scheduler:
cat /sys/block/vda/queue/scheduler
Switch your I/O Scheduler to None:
echo none > /sys/block/vda/queue/scheduler
Please do not change this if you not have enough experience in CentOS/Linux.