Windows 2012R2 QOS Feature

QOS for Storage

There are many new features in 2012R2 of which one is now QOS for storage.  So why this feature and why now?  So two points here now need to be made and really understood I think in order to understand they why now.

First VMs are now no longer going to be thought of as "another server".  What they appear to be going towards is an application on that VM.  Think of it instead of another server running 2012 but rather a SQL running a single database.  So that if this "application" then has any issue it is going to minimize the impact to the whole environment.

It also now allow us to assign or dedicate specific hardware and requirements then to our "application" VMs.  You really would not want that SQL database to absorb all the hardware IO off the storage, but without these limits it very well could - which is the nature of apps.  Same idea goes with processor limits, but this is just now in the storage realm.

So please before considering this setting - know your data and application needs.  This could seriously hinder your performance if set too low, or the inverse and impact other VM's performance.  Use tools like perfmon and such to baseline your application first.  Understanding that and then adjusting will help you in setting these limits.

So where to find and how to adjust this?

Access your VM settings through Hyper-V and explore down to the Advanced Features of your VM's hard drive.

The settings are in 8KB increments so be prepared to pull out your calculator.

It is as simple as enabling the feature and set the appropriate min and max values.