I'm a Systems Architect, and just so we're clear, the chances of losing data by disabling write barriers are close to none. You can forcefully terminate a KVM/LXC/what-have-you upmpteen hundred times before you'll see a barrier related data loss. Personally, I haven't come across one that wasn't related to a different pre-existing issue. Ext3 has barriers disabled by default, however ext4 has them enabled. As for daemons and noatime, that's also pretty unlikely as it's a horrible way to check for states. Using noatime on cPanel, and Ubuntu LAMP stacks has no consequences, only performance improvements. It's a production box, so testing the differences isn't feasible. You can go ahead and let me know the differences 