How risky is disabling barriers in /etc/fstab?

Question

linux

MySQL performance increases greatly with syslog disabled. Server installed in qemu kvm VM on Ubuntu server 16.04
/etc/fstab

UUID=5a18c97e-bd40-4b55-a2c8-ab7da4cf20f0 / ext4 errors=remount-ro,noatime,nodiratime,nobarrier 0 1

The DC power is never turned off, but this is a virtual machine. It turns out that if I unexpectedly reboot or turn off the host - the virtual machine will no longer start? How risky is nobarrier in /etc/fstab?

Answer 1

In general, many if not all modern DBMSs have a Fault Tolerance mechanism (failure protection) that works, for example, when the database is started after an emergency shutdown. So read the MySQL documentation, maybe it is implemented there too.

Answer 2

nobarrier is generally not recommended to be used, calmly remove it, nothing will break.