Q. If I enable a minimum value for Storage QoS in Windows Server 2012 R2 is an event log written?

A. Yes. If a minimum IOPS value is specified for a VHD with Storage QoS then if the IOPS for the virtual disk cannot be met a warning event ID 32930 is written to the Hyper-V-VMMS\Admin log that notifies that the required policy could not be met. Once the policy can be met an event ID 32931 will be written. Note it will never write this for maximum IOPS as Hyper-V can always enforce a maximum limit by delaying I/O. Note that the event log is written once for each resource pool rather than for every VHD