I've heard numerous times in the web hosting industry that using "too much" disk space on a drive is bad for performance. Is this just a myth? Can someone explain why this is an issue, even in a situation where the amount of IO done to the drive would be the same at 10% as it would be at 90%?
I'm especially curious in the case of virtual servers. If I set up 10 Logical volumes as the virtual disks for some VMs, is it going to run better if I "waste" 20% of the disk space?