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Figure 2-64:
Storage QoS policies and their application to different VM tiers 
Storage QoS in Windows Server 2016 is turned on by default. This means that you don’t need to 
install an additional role or feature to get going. 
For example, Figure 2-65 illustrates that if you have a Hyper-V failover cluster, you can see that a new 
cluster resource is listed. 
Figure 2-65:
Storage QoS Cluster Core Resource
You also can use the Windows PowerShell cmdlet Get-ClusterResource to display the same result: 
Get-ClusterResource -Name "Storage Qos Resource" 
Storage QoS will work effectively only if you decide to configure appropriate policies. You can use 
policies to control the traffic flow as necessary based on your requirements. You can configure 
Storage QoS policies on the SOFS. You essentially have a choice of two policy types: 

Single-instance
Using single-instance policies, you can create a minimum and maximum 
amount of IOPS per policy. This is aggregated against a VM. For example, if a VM has a single 
VHD/VHDX, it will have full use of all the IOPS in the assigned policy. However, if the VM has three 
VHD/VHDX and they are all assigned the same single-instance policy, that VM will share the 
maximum number of IOPS across all drives, degrading the overall performance. You have the 
option to have multiple single-instance policies and configure each drive to use a different single-
instance policy to ensure that they get access to all the IOPS. If you have two VMs with a single 
VHD each and all assigned to the same single-instance policy, they will also share the minimum 
and maximum IOPS. 

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CHAPTER 2 | Software-defined datacenter 

Multi-instance
With multi-instance policies, again you have options to create a minimum and 
maximum number of IOPS. However, in this scenario, if you had two VMs with a single VHD/VHDX 
each, they will get their own allocation of IOPS, both minimum and maximum. However, the same 
rules apply that if the VM had multiple disks: unless assigned individual policies, they will share 
the total amount of assigned minimum and maximum IOPS. 
To create a policy, use the following Windows PowerShell cmdlet: 
$GoldVmPolicy = New-StorageQosPolicy -Name Gold -PolicyType MultiInstance -MinimumIops 100 -MaximumIops 500
This sample will store information about the policy in the variable. There is one property called the 
PolicyId
, which you will require. To access the 
PolicyId
use the following syntax: 
$GoldVmPolicy.PolicyId 
Guid 
---- 
Cd5f6b87-fa15-402b-3545-32c2f456f6e1 
The 
Guid
is what you will require to apply this policy to a VHD by using the following Windows 
PowerShell command: 
Get-VM -Name GoldSrv* | Get-VMHardDiskDrive | Set-VMHardDiskDrive -QoSPolicyID Cd5f6b87-fa15-402b-3545-
32c2f456f6e1 
After the policy is applied, you will, of course, want to verify that the policy is indeed active, but also 
you will want to monitor if it is having the appropriate effect. You can do this by using the Get-
StorageQoSFlow cmdlet. 
The following output shows what is applied and the amount of storage the IOPS the VM is actually 
using: 
Get-StorageQosFlow -InitiatorName GoldVm1 | Format-List 
FilePath:c:\ClusterStorage\Volume1\VMS\Gold\GoldVM1.VHDX 
FlowId: ebfecb54-e47a-5a2d-8ec0-0940994ff21c 
InitiatorId : ae4e3dd0-3bde-42ef-b035-9064309e6fec 
InitiatorIOPS : 464 
InitiatorLatency : 26.2684 
InitiatorName : GoldVM1 
InitiatorNodeName : node1.contoso.com 
Interval : 300000 
Limit : 500 
PolicyId : cd5f6b87-fa15-402b-3545-32c2f456f6e1 
Reservation : 500 
Status : Ok 
StorageNodeIOPS : 475 
StorageNodeLatency : 6.5625 
StorageNodeName : node1.contoso.com 
TimeStamp : 2/12/2016 3:28:49 AM 
VolumeId : 2d34fc5a-2b3f-9922-23f4-43563b2a6787 
PSComputerName : 
MaximumIops : 100 
MinimumIops : 500 
You can use the Get-StorageQoSFlow cmdlet to validate before you create policies what the VMs are 
actually using in relation to Storage IOPS. 
Get-StorageQosFlow | Sort-Object StorageNodeIOPs -Descending | ft InitiatorName, 
@{Expression={$_.InitiatorNodeName.Substring(0,$_.InitiatorNodeName.IndexOf('.'))};Label="InitiatorNodeName"}
, StorageNodeIOPs, Status, @{Expression={$_.FilePath.Substring($_.FilePath.LastIndexOf('\')+1)};Label="File"} 
-AutoSize 
InitiatorName InitiatorNodeName StorageNodeIOPs Status File 
------------- ----------------- --------------- ------ ---- 
GoldVM5
node1 2482 Ok IOMETER.VHDX 
GoldVM2
node2 344 Ok BUILDVM2.VHDX 
GoldVM1
node2 597 Ok BUILDVM1.VHDX 
GoldVM4
node1 116 Ok BUILDVM4.VHDX 
GoldVM3
node2 526 Ok BUILDVM3.VHDX 
GoldVM4
node1 102 Ok

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CHAPTER 2 | Software-defined datacenter