Category Archives: Hyper-V

Maximum bandwidth in Hyper-V storage QoS policies

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Introduction

In a previous blog post Hyper-V Storage QoS in Windows Server 2016 Works on SOFS and on LUNs/CSV I have discussed Storage QoS Policies in Windows Server 2016. I have also demonstrated this in a lab setup at VEEAMON 2015 in one of my talks at the Microsoft presentation area. It’s one of those features where a home lab will do the job. There is no need for special storage hardware. It’s all in box functionality. Cool!

Maximum bandwidth in Hyper-V storage QoS policies

Now that was in the Technical Preview 2 and 3 era, where it all revolved around minimum and maximum QoS. In Windows Server 2016 Technical Preview 4 we got some new features in regards to storage QoS policies. One of those is that we can now also set the Maximum bandwidth on a policy using the parameter MaximumIOBandwidth. This parameter, which is set in bytes per second determines the maximum bandwidth that any flow assigned to the policy is allowed to consume.

image

We use that policy ID to assign it to the 2 shared virtual disks of our cluster nodes. You’ll need to do this for all of the guest cluster nodes.image

You can copy the PoSh demo script below


#Create a Storage Policies
$DemoVMPolicy = New-StorageQosPolicy -Name DemoVMPolicy -PolicyType MultiInstance `
-MinimumIops 250 -MaximumIops 500 -MaximumIOBandwidth 100MB

#Look at our storage Policies
Get-StorageQosPolicy -name DemoVMPolicy

#Grab our policy ID
$DemoVMPolicy = (get-StorageQosPolicy -Name DemoVMPolicy).PolicyId 
$DemoVMPolicy 


#Look at our VMs policy setting before and after assigning a storage policy.
#We assign the storage policy to the 2 shared virtual disks
#that are located a location 1 and 2 on SCSI controller 0

Get-VM -Name GuestClusterNode1 | Get-VMHardDiskDrive |
ft Path,MinimumIOPS, MaximumIOPS, MaximumIOBandwidth, QoSPolicyID -AutoSize

Get-VM -Name GuestClusterNode1 | Get-VMHardDiskDrive | Where-Object {$_.controllerlocation -ge 1}|
Set-VMHardDiskDrive  -QoSPolicyID $DemoVMPolicy

Get-VM -Name GuestClusterNode1 | Get-VMHardDiskDrive | 
ft Path, MinimumIOPS, MaximumIOPS, MaximumIOBandwidth, QoSPolicyID -AutoSize

You can use MaximumIOBandwidth by itself or you can combine it with the maximum IOPS setting. When both of these parameter are set in a storage QoS policy they are both active. The one that is reached first by a flow assigned to this policy will be the limiting factor in the I/O of that flow.

As an example. Let’s say you specify 500 IOPS and 100Mbps bandwidth as maxima. Your workload hits 500 IOPS but only consumes 58 Mbps it’s the IOPS that are limiting the flow.

A first look at shared virtual disks in Windows Server 2016

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Introduction to shared virtual disks in Windows Server 2016

Time to take a first look at shared virtual disks in Windows Server 2016 and how they are set up. Shared VHDX was first introduced in Windows Server 2012 R2. It provides shared storage for use by virtual machines without having to “break through” the virtualization layer. This way is still available to us in Windows Server 2016. The benefit of this is that you will not be forced to upgrade your Windows Server 2012 R2 guest clusters when you move them to Windows Server 2016 Hyper-V cluster hosts.

The new way is based on a VHD Set. This is a vhds virtual hard disk file of 260 MB and a fixed or dynamically expanding avhdx which contains the actual data. This is the “backing storage file” in Microsoft speak. The vhds file is used to handle the coordination of actions on the shared disk between the guest cluster nodes?

Note that an avhdx is often associated with a differencing disk or checkpoints. But the “a” stands for “automatic”. This means the virtual disk file can be manipulated by the hypervisor and you shouldn’t really do anything with it. As a matter of fact, you can rename this off line avhdx file to vhdx, mount it and get to the data. Whether this virtual disk is fixed or dynamically expanding doesn’t matter.

You can create on in the GUI where it’s just a new option in the New Virtual Hard Disk Wizard.

Or via PowerShell in the way you’re used to with the only difference being that you specify vhds as the virtual disk extension.

In both cases both vhds and avhdx are created for you, you do not need to specify this.

You just add it to all nodes of the guest cluster by selecting a “Shared Drive” to add to a SCSI controller …

… browsing to the vhds , selecting it and applying the settings to the virtual machine. Do this for all guest cluster nodes

Naturally PowerShell is your friend, simple and efficient.

Rules & Restrictions

As before shared virtual disk files have to be attached to a vSCSI controller in the virtual machines that access it and it needs to be stored on a CSV. Both block level storage or a SMB 3 file share on a Scale Out File Server will do for this purpose. If you don’t store the shared VHDX or VHD Set on a CSV you’ll get an error.

Sure for lab purposes you can use an non high available SMB 3 share “simulating” a real SOFS share but that’s only good for your lab or laptop.

The virtual machines will see this shared VHDX as shared storage and as such it can be used as cluster storage. This is an awesome concept as it does away with iSCSI or virtual FC to the virtual machines in an attempt to get shared storage when SMB 3 via SOFS is not an option for some reason. Shared VHDX introduces operational ease as it avoids the complexities and drawbacks of not using virtual disks with iSCSI or vFC.

In Windows Server 2012 R2 we did miss some capabilities and features we have come to love and leverage with virtual hard disks in Hyper-V. The reason for this was the complexity involved in coordinating such storage actions across all the virtual machines accessing it. These virtual machines might be running on different hosts and, potentially the shared VHDX could reside on different CSVs. The big four limitations that proved to be show stopper for some use cases are in my personal order of importance:

  1. No host level backup
  2. No on line dynamic resize
  3. No storage live migration
  4. No checkpoints
  5. No Hyper-V Replica support

I’m happy to report most of these limitations have been taken care of in Windows Server 2016. We can do host level backups. We can online resize a shared VHDX and we have support for Hyper-V replica.

Currently in 2016 TPv4 storage live migration and checkpoints (both production and standard checkpoints) are still missing in action but who knows what Microsoft is working on or has planned. To the best of my knowledge they have a pretty good understanding of what’s needed, what should have priority and what needs to be planned in. We’ll see.

Other good news is that shared VHDX works with the new storage resiliency feature in Windows Server 2016. See Virtual Machine Storage Resiliency in Windows Server 2016 for more information. Due to the nature of clustering when a virtual machine loses access to a shared VHDX the workload (role) will move to another guest cluster node that still has access to the shared VHDX. Naturally if the cause of the storage outage is host cluster wide (the storage fabric or storage array is toast) this will not help, but other than that it provides for a good experience. The virtual machine guest cluster node that has lost storage doesn’t go into critical pause but keeps polling to see if it regains access to the shared VHDX. When it does it’s reattached and that VM becomes a happy fully functional node again.

It also supports the new Storage Qos Policies in Windows Server 2016, which is something I’ve found during testing.

Thanks for reading!

Hyper-V Amigos Chat at the Grand Canyon

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image

Yes, you read that correctly, there was a Hyper-V Amigos Chat at the Grand Canyon. Last year, during the last week of October and the first week of November in 2015 my friend Carsten Rachfahl (@hypervserver) and I were in in the USA for Veeam’s VEEAMON 2015 and the Microsoft Global MVP Summit. In between those two events, we – two of the legendary Hyper-V Amigos – had to telecommute. No problems for us, we’re masters at remote working. We’re agile, flexible, dynamic, resourceful and mobile so we drove to the Grand Canyon to muse on our thoughts and recorded some videos on our experience at VEEAMON 2015 and our first experiences with the Windows server 2016 Technical Previews so far.

The results are nothing but amazing footage of a Hyper-V Amigos chat at the Grand Canyon. Both Hyper-V MVPs, Veeam Vanguards and Dell Tech Center Rockstars discuss what they know best and love to do whilst on their way to the Microsoft MVP Summit in a roundabout kind of way Smileimage

Enjoy people, have a great 2016. Click on the image above or follow this link:Hyper-V Amigos Chat at the Grand Canyon. More info on these technologies can also be found at http://hyper-v-amigos.net and http://hyper-v-server.de.

A first look at shared virtual disks in Windows Server 2016

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Introduction

Time to take a first look at shared virtual disks in Windows Server 2016 and how they are set up. Shared VHDX was first introduced in Windows Server 2012 R2. It provides shared storage for use by virtual machines without having to “break through” the virtualization layer. This way is still available to us in Windows Server 2016. The benefit of this is that you will not be forced to upgrade your Windows Server 2012 R2 guest clusters when you move them to Windows Server 2016 Hyper-V cluster hosts.

The new way is based on a VHD Set. This is a vhds virtual hard disk file of 260 MB and a fixed or dynamically expanding avhdx which contains the actual data. This is the “backing storage file” in Microsoft speak. The vhds file is used to handle the coordination of actions on the shared disk between the guest cluster nodes?

Note that an avhdx is often associated with a differencing disk or checkpoints. But the “a” stands for “automatic”. This means the virtual disk file can be manipulated by the hypervisor and you shouldn’t really do anything with it. As a matter of fact, you can rename this off line avhdx file to vhdx, mount it and get to the data. Whether this virtual disk is fixed or dynamically expanding doesn’t matter.

You can create on in the GUI where it’s just a new option in the New Virtual Hard Disk Wizard.

Or via PowerShell in the way you’re used to with the only difference being that you specify vhds as the virtual disk extension.

In both cases both vhds and avhdx are created for you, you do not need to specify this.

You just add it to all nodes of the guest cluster by selecting a “Shared Drive” to add to a SCSI controller …

… browsing to the vhds , selecting it and applying the settings to the virtual machine. Do this for all guest cluster nodes

Naturally PowerShell is your friend, simple and efficient.

Rules & Restrictions

As before shared virtual disk files have to be attached to a vSCSI controller in the virtual machines that access it and it needs to be stored on a CSV. Both block level storage or a SMB 3 file share on a Scale Out File Server will do for this purpose. If you don’t store the shared VHDX or VHD Set on a CSV you’ll get an error.

Sure for lab purposes you can use an non high available SMB 3 share “simulating” a real SOFS share but that’s only good for your lab or laptop.

The virtual machines will see this shared VHDX as shared storage and as such it can be used as cluster storage. This is an awesome concept as it does away with iSCSI or virtual FC to the virtual machines in an attempt to get shared storage when SMB 3 via SOFS is not an option for some reason. Shared VHDX introduces operational ease as it avoids the complexities and drawbacks of not using virtual disks with iSCSI or vFC.

In Windows Server 2012 R2 we did miss some capabilities and features we have come to love and leverage with virtual hard disks in Hyper-V. The reason for this was the complexity involved in coordinating such storage actions across all the virtual machines accessing it. These virtual machines might be running on different hosts and, potentially the shared VHDX could reside on different CSVs. The big four limitations that proved to be show stopper for some use cases are in my personal order of importance:

  1. No host level backup
  2. No on line dynamic resize
  3. No storage live migration
  4. No checkpoints
  5. No Hyper-V Replica support

I’m happy to report most of these limitations have been taken care of in Windows Server 2016. We can do host level backups. We can online resize a shared VHDX and we have support for Hyper-V replica.

Currently in 2016 TPv4 storage live migration and checkpoints (both production and standard checkpoints) are still missing in action but who knows what Microsoft is working on or has planned. To the best of my knowledge they have a pretty good understanding of what’s needed, what should have priority and what needs to be planned in. We’ll see.

Other good news is that shared VHDX works with the new storage resiliency feature in Windows Server 2016. See Virtual Machine Storage Resiliency in Windows Server 2016 for more information. Due to the nature of clustering when a virtual machine loses access to a shared VHDX the workload (role) will move to another guest cluster node that still has access to the shared VHDX. Naturally if the cause of the storage outage is host cluster wide (the storage fabric or storage array is toast) this will not help, but other than that it provides for a good experience. The virtual machine guest cluster node that has lost storage doesn’t go into critical pause but keeps polling to see if it regains access to the shared VHDX. When it does it’s reattached and that VM becomes a happy fully functional node again.

It also supports the new Storage Qos Policies in Windows Server 2016, which is something I’ve found during testing.

Thanks for reading!