IT Manager with 51-200 employees

Apr 27, 2014

Virtual Networking: VMware vs. Hyper-V

We've been busy building out our new Server 2012/Hyper-V infrastructure in support of our move to all new and shiny Exchange 2013, SharePoint 2013, Lync 2013 and Office 2013 along with our move to Windows 8 on all the client machines. We made the decision to move off VMware ESXi as our virtualization platform and onto Hyper-V as we are first and foremost a Microsoft shop. Server 2012 and Hyper-V now offer a compelling platform for virtualization and, frankly, if we can do what we want to do with products from one vendor rather than multiple vendors then so much the better. Hyper-V is no longer a poor relation to VMware in terms of performance or capabilities and, believe me, I was the most “dyed in the wool” rabid VMware user for many years so I’m not saying this just to toe the company line. I firmly believe that it’s now pretty much a level playing field between VMware and Microsoft.

During our migration we have been learning about the subtle differences between the two platforms and have had to adjust our thinking accordingly. Virtual networking, and specifically “virtual switches”, is one area where we have had to really make a conscious effort to adjust how we look at things and how we configure things. Let me explain …

In both VMware and Hyper-V you have to deal with virtual switching to “bridge” the virtual machines hosted on a virtualization host to your physical network. Both platforms allow you to create virtual switches that act pretty much the same a physical layer 2 switches and both platforms require you to create at least one virtual switch before VM’s can be connected to the outside world. But while the overall concept is the same the execution varies rather a lot between the two platforms.

VMware Virtual Switch

In VMware I can create a virtual switch and attach one or more physical NIC’s to the switch. If I create a virtual switch with 2 NIC’s then the switch would have theoretical throughput of 2Gbps assuming both underlying physical NIC’s were gigabit. When I attach VM’s to the switch the VM’s would route traffic over both NIC’s (in theory). I know in practice that traffic might “ping pong” across the NIC’s as they aren’t actually teamed together (bonded) but the point is the switch provides “bigger” bandwidth than a switch with only one NIC attached. (You can bond NIC’s for switches but that is beyond the scope of this blog.) Think of the switch as providing “load balancing” across the attached NIC’s as well as a certain amount of redundancy as the switch (and the attached VM’s) can survive a component NIC failure and keep connectivity in place. Our VMware configs usually had a couple of switches configured, each with a couple of NIC’s, and each switch would support multiple VM’s. VMware virtual switches normally do NOT have an IP assigned to the switch as underlying VMware doesn’t attempt to bind an IP to the physical NIC.

Here is the list of physical NIC’s in my lab ESXi box, one NIC is currently connected to the physical network:

And here is the current switch configuration:

In this case the switch is the default one created at installation time. It includes the single cabled NIC I have in place right now. Note that there are actually two networks configured – VM Network and Management Network. The Management Network actually has an IP address assigned as that is the IP address for the VMware host itself. In many cases when a VMware host has many NIC’s the Management Network might have a NIC all to itself. The VM Network provides switch connectivity to the VM’s attached to it and an IP address is NOT assigned to the network. Note: as there is only one NIC assigned to the switch connectivity to both the host and the VM’s would be lost if the NIC failed or was disconnected from the network.

As you can see I have now added a second virtual switch (it has a NIC that is NOT cabled in to the physical network at this point). I have removed the VM Network from the first virtual switch (vSwitch0) and added a new network, VM Network 2, to the second virtual switch (vSwitch1). Now I have completely segmented my management network (physical host access) from my virtual machine network (virtual machine access). In this case the host would be accessible from the physical network as its switch (vSwitch0) has an operational NIC attached. The Server 2012 VM on vSwitch1 would NOT be accessible from the physical network as its switch does not have an operational (cabled in) NIC attached.

And now I have removed the second virtual switch, added the second NIC to the first virtual switch and moved the Server 2012 VM back on to the VM Network on the switch. In this case both the host and the VM would be accessible from the physical network as the switch has at least one operational NIC attached to it.

VMware virtual switching is pretty configurable and elastic.

Hyper-V Virtual Switch

Hyper-V virtual switches do NOT have the same ability to bind multiple NIC’s into a switch config, at least not at the virtual switch level. Traditional Hyper-V “external switches” work on the paradigm of one physical host NIC being bound to the switch. If you have a server with a whole bunch of NIC’s then you would need to create a virtual switch for each NIC that you want to use with Hyper-V. Each switch can support multiple VM’s attached to it, just like VMware, but each switch can only have the one physical NIC bound to it.

With the advent of Server2012 and Hyper-V 3 the single NIC constraint can be circumvented by TEAMING NIC’s at the Server 2012 level through Server Manager. The resulting tNIC can then be selected as the “NIC” for a Hyper-V virtual switch and the virtual switch would then have the aggregated bandwidth of the underlying NIC’s. The caveat here is that the PHYSICAL SWITCH on the other end of the cables from the NIC’s has to also allow for port teaming either via a manual set up or via LACP.

The other thing to understand is that the virtual switch will “take over” most of the characteristics of the NIC/tNIC assigned to it. That means the virtual switch will take on the IP address – DHCP or STATIC – of the underlying NIC as the NIC is just a NIC to the Windows Server host. This is very important to understand when you are setting up Hyper-V, specially so on a single NIC server.

Here is the adapter configuration on my lab Hyper-V server:

This is pretty similar to my VMware server, I have two physical NIC’s but only one is actually cabled into the physical network at this time. You’ll also note the “vEthernet” connection, this is the single Hyper-V virtual switch that has been created on this box.

In the Hyper-V Manager on the server I see the following for the virtual switch config:

This is the switch that I created to support my first Hyper-V VM’s. It is created as an “External Network” which means that it provides connectivity between the attached VM’s and the physical network beyond the Hyper-V host. And, importantly, it is set to, “Allow management operating system to share the network adapter”. This is critical in a single NIC server or, as in my case, when there is only one connected NIC on a multi-NIC machine. This setting is analogous to the VMware “Management Network” in that it is what allows the Server 2012 host to “share” the NIC with the Hyper-V guests attached to the switch. If I had created this switch and NOT selected this setting I would have ended up NOT being able to access the HOST over the network as the switch would NOT share the NIC between the VM’s and the host (single operational NIC, remember?). When this setting is selected, the switch will take on many of the characteristics of the underlying NIC including its network address settings (DHCP or Static); therefore, the switch will bind itself to the IP assigned to the HOST.

This is a really important concept to grasp because I cannot create a switch and assign multiple NIC’s to it (as mentioned previously). If I have a server with a bunch of NIC’s and I go and create one virtual switch per physical NIC AND I select the “Allow management setting …” then I will be binding multiple IP addresses to my host and that is probably not what I want to do. In our office our sysadmin, Louis, was wondering why all of a sudden the Hyper-V host had pulled a bunch of DHCP addresses; the answer was he created a bunch of switches all of which had management turned on which, in turn, required an IP and the default setting is DHCP.

Note that the switch IP, if there is one, has no bearing on the IP’s assigned to the VM’s nor do the VM’s require the switch to have an assigned IP. If a switch has an IP then it is there strictly to provide connectivity passthrough to the host.

As you might imagine, it is not as easy to configure Hyper-V virtual networking to be as “elastic” as VMware virtual networking, VMware still outshines Microsoft in this regard. You CAN use NIC teaming at the Server 2012 level to create tNIC’s (teamed NIC’s) that can then be incorporated into Hyper-V virtual switches but there are caveats that have to be met. Your physical switches must “understand” how you have teamed the NIC’s and be configured (or configure themselves) accordingly. Also, depending on how the NIC’s are teamed there is the possibility of tNIC failure if an underlying teamed NIC fails. If a tNIC in a Hyper-V switch fails then the switch itself will fail. This is very different behaviour from that of the VMware virtual switching that I have discussed and it is something you need to understand as you move from VMware to Hyper-V.

Conclusion

VMware still has the edge on Microsoft when it comes to simple virtual switching (and simple is what we deal with in the SMB world). But the edge is slim and Hyper-V does offer real value and a compelling use argument. Like anything else in IT, you need to understand the strengths and weaknesses of the products you select and design your environment accordingly. I hope this discussion of VMware and Hyper-V virtual switching will help you in your endeavours.

Disclosure: My company does not have a business relationship with this vendor other than being a customer.

it_user250662Works

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Jun 5, 2015

I am not sure about the last statement as even with VMWare you still need to go in and configure multiple NIC's on one switch for LACP, Active Passive, IP Hash, MAC Hash....... the only difference I can see is where the linking of the NIC's happens. Microsoft is before adding the Virtual NIC to the Switch, VMWare is after the switch is created and addition NIC's are added

it_user91356

Vice President at a tech vendor with 51-200 employees

Apr 15, 2014

Hyper-V can be run on this Dell PowerEdge

Hyper-V can be run on this Dell PowerEdge C6220.

Here is a brief upbeat compelling video overview of the Dell PowerEdge C6220 and C6220 II. https://www.youtube.com/watch?v=aJZs2EUy9Vg

Disclosure: My company does not have a business relationship with this vendor other than being a customer.

it_user80895IT Manager at a educational organization with 501-1,000 employees

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Apr 16, 2014

Hello,

Yes Hyper-V works and is supported on Dell PowerEdge C6220.
This is confirmed by Dell.

Good luck!

Regards,
Charbel

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it_user79785

Director of IT with 51-200 employees

Jan 19, 2014

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Replica, Cost and Stability are very valuable but support has only been average - has proven to be hit-or-miss

What is most valuable?

There are a few features that make the product stand out:

Replica: We have Replica running in our NY & London datacenters and can (and on a couple of occasions, have) fail over servers quickly and cleanly. Failback also worked like a charm.
Cost: It’s no secret that H-V is much less expensive than VMware; we are saving many thousands a year in licensing & support. It also sets up for future costs savings as the business grows.
Stability: Since we implemented the H-V solution we have reported outstanding uptimes.

How has it helped my organization?

The prime example is the simplicity and cost savings of our new DR/BCP solution. By consolidating our two disparate corporate AD2008/VMWare domains into a single Hyper-V/AD 2012 domain we have:

Drastically reduced the complexity of the environment. NO more kludges or 3rd-party software to get systems like Exchange, Lync or AD Users conversing seamlessly.
About $150K a year in colocation costs. With our private cloud we have a built-in DR/BCP solution on existing infrastructure, no need to farm out to a colo provider.

What needs improvement?

To be determine – we will be conducting a review of the R2 release in the second quarter of 2014.

For how long have I used the solution?

We’ve had the system in place since January 2013 and it went into full production in May 2013.

What was my experience with deployment of the solution?

Not outside the usual challenges in learning a new application. We had 4 months to design, install and run the new domain in parallel to former environments.

What do I think about the stability of the solution?

Outside of needing to keep the VM hosts patched (we did have an issue with a driver related to storage), no.

What do I think about the scalability of the solution?

Zero – we have a pretty robust infrastructure in place for the number of staff. Clustered DL385’s & EMC VNXe at each datacenter will allow us to scale out and up easily (we are using around 12% of capacity on the VNXe and can drop additional servers into the cluster if there’s a spike in use or we make acquisitions).

How are customer service and technical support?

Customer Service: Good.Technical Support: Average. I say that as my experience with MSFT Support in general has proven to be hit-or-miss with the first-level support. The second-level support is much better and I haven’t had to go beyond them for solutions.

Which solution did I use previously and why did I switch?

We had VMware/AD 2008 in place at the two companies; the US infrastructure was already built out with SAN and meshed networking so we had to play catch-up with the UK datacenter. The switch was made at the behest of the group CEO – what the boss wants the boss gets!

How was the initial setup?

Pretty straightforward without any major surprises. The online documentation written up by MSFT and the legion of fans proved to be invaluable. The setup of Replica proved to be very easy.

What about the implementation team?

Implementation was done mostly by in-house staff (2 of us) and we needed a hand from a VAR for some of the clustering setup.

What's my experience with pricing, setup cost, and licensing?

Between the additional hardware/software and consultant costs we spent around $80K.

Which other solutions did I evaluate?

No – we felt the two best solutions were VMware & MSFT as we had been using VMware and had many years of experience with MSFT products.

What other advice do I have?

Do not be afraid to work $$$ into the budget in case you need assistance from a 3rd-party.
Test in parallel and do not be a hero and try to do it whole-hog at once.
Do not postpone the DR/BCP part of the project. If you are building out a new infrastructure DO THIS FIRST. We were forced to push this to the back of the project and it bit us for a few days; in the end you do what the executives say but having file/application/server/site disaster recovery is an absolute must before you migrate production data.
If you haven’t gone too far with it do a review of R2; it provides many improvements in the VM & Replica features.

Disclosure: My company does not have a business relationship with this vendor other than being a customer.

it_user1122

Infrastructure Expert at a tech services company with 1,001-5,000 employees

Nov 18, 2013

Even better than before

Last time I wrote a review on Hyper V for 2008 R2, which is the product I was using at the time. Having had experience with Hyper V "3.0", the version included in 2012, I figured it was time to update my review.

Pro's

Hyper-V definitely has its pros!

- This version of Hyper-V is even more in depth than before, bringing it up to par with and even surpassing vSphere in some ways.

- PowerShell scripting has been greatly expanded upon, allowing for more automation and centralized management.

- Exporting a VM and importing it into a new server, or setting up fail-over clustering is easier than ever!

- The integration with the new server manager and the existing MMC substructure is superb.

Cons:
The cons are the same as the last time.

- Individual licensing costs for each server.
- If you aren't using Hyper-V Core and are running Hyper-V on top of the full Server 2008 R2 platform, then you have less resources to allocate to your Virtual Machines.
- Except through RDP or SCVMM, there is no way to access the VM's on alternative platforms (like Mac or Linux).

All in all, Microsoft Hyper-V is an excellent platform and a great competitor for VMWare, and it keeps improving with each iteration!

Disclosure: My company does not have a business relationship with this vendor other than being a customer.

it_user3396Team Lead at Tata Consultancy Services

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Nov 19, 2013

Cool Marcos,

Would you be kind enough to add those missing features :>)

Thanks

Henry

See all 4 comments

it_user8256

Senior Manager of Infrastructure with 501-1,000 employees

Oct 2, 2013

Configuring and Managing Hyper-V Replica

Management Considerations
Hyper-V servers are managed locally using the Hyper-V Manager interface or remotely using the Hyper-V Remote Server Administration Tools (RSAT) or System Center Virtual Machine Manager (SCVMM). If the configuration is a Hyper-V Failover Cluster, the Failover Cluster Management interface is used.

Configuration and Management UI
Hyper-V Replica settings are configured in the Hyper-V Manager interface for standalone Hyper-V servers and the Failover Cluster Manager interface for Hyper-V Failover Clusters.

Configuration Settings

Configuring a Standalone Hyper-V Replica Server
1. In the Hyper-V Manager interface, Click on Hyper-V Settings in the Actions pane
2. In the Hyper-V Settings dialog box, Click on Replication Configuration
3. In the Details pane, Select Enable this computer as a replica server
4. Choose an Authentication method to include the port that will be used (The default ports are 80 for HTTP and 443 for HTTPS). There are default firewall rules already in place that just need to be enabled when replication is enabled on the Hyper-V server.
5. Configure Authorization and storage. This includes designating a specific location to store replica virtual machine files if the default location is not to be used. Should you not desire to allow all Primary servers to be serviced, there is an option to allow only specific servers (Primary servers) to send replication requests. If you want to allow all servers within the domain, a wildcard character can be used (e.g. *.contoso.com). When using a wildcard, only one storage location can be specified. If individual server entries are used, different storage locations for replica files can be configured. Complete all entries for the Primary Server, Storage Locations, and Security Tag information. Click Apply or OK when finished.

Configuring a Hyper-V Replica Failover Cluster
A Failover Cluster consists of multiple physical servers also known as nodes. Each node must have the Hyper-V role installed as well as the Failover Clustering feature. Installation of the Hyper-V role has already been covered. To install the Failover Clustering feature:
1. In Server Manager, start the Add Roles and Features Wizard (ARFW) by first choosing the Dashboard view and then choose Add Roles.
2. Step through the ARFW choosing the local node and making the following choices:
a. Installation Type: Role-based or Feature-based installation
b. Server Selection: Choose local node
c. Server Roles: Make no selections and click Next
d. Features: Choose Failover Clustering
e. Confirmation: Review the information and click Install (a reboot is not required when installing the Failover Clustering feature)
f. Results: Ensure the result is a successful installation of the Failover Clustering feature.
3. Complete this action across all nodes that will be members in the cluster
NOTE: The Failover Clustering feature can also be installed from the command line interface (CLI) by using the Deployment Image and Service Management (DISM) command line tool. At a command prompt, type: dism /online /enable-feature /featurename:Failover-Clustering. A reboot is not required to complete the installation.

After the Failover Clustering feature is installed and a Failover Cluster is created, the Hyper-V Replica Broker Role needs to be configured. To create the Hyper-V Replica Broker role:
1. Open the Failover Cluster Manager interface (located under Tools in the Server Manager Menu bar)
2. In the left-pane, connect to the cluster
3. With the name of the cluster highlighted in the left-hand pane, click on Configure Role in the Actions pane
4. The High Availability Wizard initializes
5. Select Hyper-V Replica Broker in the Select Role screen
6. Complete the wizard by providing a properly formatted NetBIOS name and IP address (as needed) which serves as the connection point (Client Access Point (CAP))when configuring virtual machines for replication
7. Ensure the Role comes Online and is able to failover between all nodes in the cluster

Configuring the Failover Cluster as a Replica cluster

With the Hyper-V Replica Broker Role configured in the cluster, the cluster can be configured as either a Primary cluster or a Replica cluster. This is accomplished using the Highly Available Hyper-V Replica role. To accomplish this:
1. Open the Failover Cluster Manager interface (located under Tools in the Server Manager Menu bar)
2. In the left-pane, connect to the cluster
3. With the name of the cluster highlighted in the left-hand pane, click on Roles in the details pane under the Navigate category
4. Right-click on the Role and choose Replication Settings
5. In the Hyper-V Replica Clustering Broker Configuration screen, make the appropriate selections as needed to configure the cluster as a Replica server.

This action implements the configuration across all nodes in the cluster. Keep in mind this does not automatically enable the correct firewall rules in each node of the cluster nor does it properly configure authentication if certificates are being used. Those actions will have to be completed by the administrator on each node in the cluster. When using certificate based authentication in a Failover Cluster, all of the cluster nodes and the Client Access Point (CAP) supporting the Hyper-V Replica role will need machine certificates.

Disclosure: My company does not have a business relationship with this vendor other than being a customer.

it_user8256

Senior Manager of Infrastructure with 501-1,000 employees

Oct 2, 2013

Enabling a Virtual Machine for Replication

Replication is configured on a per virtual machine basis. Virtual machines running on Primary site Hyper-V servers (or Hyper-V Failover Clusters) are configured to replicate to Replica servers (or Replica Failover Clusters) at remote sites.
1. In Hyper-V Manager, in the Details pane, Click on a virtual machine
2. With a virtual machine selected, Right-click and choose Enable Replication. This starts the Enable Replication wizard
3. In the Specify Replica Server screen, enter either the NetBIOS or the Fully-Qualified Domain Name (FQDN) for the Replica Server in the Replica Server box. (Note: If the Replica server is a Failover Cluster, ensure the connection point for the Hyper-V Replica Broker is used). Click Next

4. If Remote WMI is enabled, then Hyper-V Replica automatically fills the port and authentication settings
5. In the Choose Replication VHDs screen, deselect the disk(s) you do not want to replicate for the virtual machine and then click Next
6. Replication changes are sent to a Replica server every 5 minutes. In the Configure Recovery History screen, make selections for the number and types of recovery points to be sent to the Replica server. If Only the latest point for recovery is chosen, then there will be only the parent VHD that is sent during Initial Replication and all changes are merged into that VHD. If Additional recovery points is chosen, set the number of desired additional recovery points (Standard Replicas) that will be saved on the Replica server. The final selection in this screen, Replicate incremental VSS copy every : (available only if Recovery History is enabled) can be used to save Application-consistent Replicas for the virtual machine on the Replica server. After completing the selections, Click Next

7. In the Choose Initial Replication Method screen, several methods can be used to perform an initial replication for the virtual machine to the Replica server. The default selection is to Send initial copy over the network. This starts replication immediately over the network to the Replica server. If immediate replication is not desired, it can be scheduled to occur at a specific time on a specific date. If the administrator does not want to consume the bandwidth due perhaps to the large amount of data that needs to be replicated, he can choose Send initial copy using external media. This method copies all the virtual machine data to a portable storage device that can then be sent to a Replica site and the initial replication can be completed there by importing the data. The final option available to an administrator is Use an existing virtual machine on the Replica server as the initial copy. A restored virtual machine or snapshot of a virtual machine on the Replica server will be used as the initial copy. Make a selection and then Click Next

8. In the Completing the Enable Replication Relationship Wizard, review the information in the Summary and then Click Finish
9. A pop-up dialog box is presented indicating replication was successfully enabled for the virtual machine. In the dialog box is a Settings button that can be used to configure the network the replica virtual machine will connect to on the Replica server. This can be useful because the replica virtual machine is not connected to any network on the Replica server by default
The Enabling Replication process will start and should complete successfully (i.e. a virtual machine is created on the Replica server and delta replication commences. If the Replica server is a Failover Cluster, the virtual machine is made highly available). If any errors occur, refer to the troubleshooting section later in this document.

Once the replication relationship is established and if Send initial copy over the network was selected (Default setting), the Status column for the configured virtual machine will indicate Sending Initial Replica. Progress as a percentage of the total replication is also displayed.
Note: If a virtual machine is being replicated to a Failover Cluster (using the Hyper-V Replica Broker), a highly available virtual machine is created in the cluster. This allows the replica to be migrated to other nodes in the cluster if needed.
If Send initial copy using external media was selected, the Status for the virtual machine will indicate an Initial Replication in Progress. In this case, the progress reflects the copying of the virtual machine files to a location other than the Replica Server (perhaps a portable storage device) so the files can be transported to the Replica server location and then the Initial Replication can be completed by importing the files on that server. Once the import process completes, the Replication State for the virtual machine in the Primary Site will reflect a new Replication State of Replication Enabled.
If Use existing restored virtual machine as initial copy was selected, the virtual machine files restored from a backup on the Replica server will be used for Initial Replication (IR). Before delta replication actually begins, a quick resynch is executed.

Hyper-V Replica implements the standard Hyper-V virtual machine folder structure on the Replica server in the location specified when the Replica server (Replica Failover Cluster) is configured. A Hyper-V Replica folder is created as the root folder in the specified location. Under the Hyper-V Replica folder is a series of subfolders as seen here -

NOTE: The Snapshots folder is not created unless Recovery History is configured for the virtual machine.

The folders support the necessary files for each virtual machine configured to replicate with the Replica server. The virtual machines are identified by Globally Unique Identifiers (GUID) as seen here -

Disclosure: My company does not have a business relationship with this vendor other than being a customer.

it_user8256

Senior Manager of Infrastructure with 501-1,000 employees

Oct 2, 2013

Management Tasks for Hyper-V 2012

The Hyper-V Manager interface is used to manage standalone Hyper-V Primary, Replica servers, and the virtualized workloads running on those servers. The Failover Cluster Manager interface is used if the Primary or Replica servers are part of a Hyper-V Failover Cluster. Hyper-V Replica management tasks can be categorized as follows:
 Hyper-V Server Primary Site Management Tasks
 Hyper-V Server Replica Site Management Tasks
 Virtual Machine Primary Site Management Tasks
 Virtual Machine Replica Site Management Tasks
 Modifying Virtual Machine Replication Settings
Note: In the above list, Hyper-V Failover Cluster can be substituted for 'Hyper-V Server'.

Hyper-V Server Primary Site
Management tasks involving the Hyper-V Server at a Primary Site include:
 Ensure the Hyper-V server (Hyper-V Failover Cluster) at the Primary site is configured as a Replica server to support Reverse Replication for a Planned Failover event

To configure the Hyper-V server at the Primary site as a Replica server:
1. In the Hyper-V Manager interface, Click on Hyper-V Settings in the Actions pane
2. In the Hyper-V Settings dialog box, Click on Replication Configuration
3. In the Details pane, Select Enable this computer as a Replica server
4. Choose an Authentication method to include the port that will be used (if not using the default port)
5. Configure Authorization and storage. This includes designating a specific location to store replica virtual machine files if the default location is not to be used. Should you not desire to allow all Hyper-V Primary servers to be serviced, you have the option to allow only specific Hyper-V servers (Primary servers) to send replication requests. Click Apply or OK when finished
Note: In a Replica cluster, use the Hyper-V Replica Broker role to configure the cluster nodes for replication.

 Monitor the Replication Health of virtual machines configured for replication

To monitor the Replication Health of a virtual machine configured for replication:
1. Open Hyper-V Manager
2. In the details pane, Right-click on one of the Column Headings and select Add\Remove Columns
3. Choose Replication Health in the Available Columns list, click Add to move it to the Displayed Columns list
4. Move the new column to the desired location in the listing and click OK

 Monitor Hyper-V Replica specific Performance counters using Performance Monitor

To monitor Hyper-V Replica performance:
1. Click the Start button, then click Run and type perfmon.msc and press ENTER
2. In the navigation tree, expand Monitoring Tools, and then click Performance Monitor
3. In the menu bar above the Performance Monitor graph display, either click the Add button (+) or right-click anywhere in the graph and click Add counters from the menu. The Add Counters dialog box opens
4. In the Available Counters section, select counters to view in the Performance Monitor display. The counters for Hyper-V Replica are virtual machine specific and are listed under Hyper-V F Counter VM
5. Choose the desired counters and instances (virtual machines) then click the Add button to add the counters
6. When finished, click OK
For more information Performance Monitor, visit the Performance Monitor Getting Started Guide (http://technet.microsoft.com/en-us/library/dd744567(WS.10).aspx) on TechNet.

 Evaluate Hyper-V Replica log data using the Microsoft-Windows-Hyper-V-VMMS\Admin log

To review Hyper-V Replica log data:
1. In the Server Manager Menu Bar, Click on Tools and choose Event Viewer from the list
2. In the navigation tree, expand Application and Services Logs, expand Microsoft, expand Windows, expand Hyper-V-VMMS
3. Click on Admin
Hyper-V Replica event messages are registered in the Hyper-V-VMMS channel.

Hyper-V Server Replica Site
Management tasks involving the Hyper-V Server at a Replica Site include:
 Ensure the Hyper-V server (Hyper-V Failover Cluster) at the Replica site is configured as a Replica server
To configure the Hyper-V server at the Primary site as a Replica server:
1. In the Hyper-V Manager interface, Click on Hyper-V Settings in the Actions pane
2. In the Hyper-V Settings dialog box, Click on Replication Configuration
3. In the Details pane, Select Enable this computer as a Replica server
4. Choose an Authentication method to include the port that will be used (if not using the default port)
5. Configure Authorization and storage. This includes designating a specific location to store replica virtual machine files if the default location is not to be used. Should you not desire to allow all Hyper-V Primary servers to be serviced, you have the option to allow only specific Hyper-V servers (Primary servers) to send replication requests. Click Apply or OK when finished

Note: In a Replica cluster, use the Hyper-V Replica Broker role to configure the cluster nodes for replication.

 Monitor the Replication Health of virtual machines configured for replication

 Monitor Hyper-V Replica specific Performance counters using Performance Monitor

To monitor Hyper-V Replica performance:
1. Click the Start button, then click Run and type perfmon.msc and press ENTER
2. In the navigation tree, expand Monitoring Tools, and then click Performance Monitor
3. In the menu bar above the Performance Monitor graph display, either click the Add button (+) or right-click anywhere in the graph and click Add counters from the menu. The Add Counters dialog box opens
4. In the Available Counters section, select counters to view in the Performance Monitor display. The counters for Hyper-V Replica are virtual machine specific and are listed under Hyper-V Replica Counter VM
5. Choose the desired counters and instances (virtual machines) then click the Add button to add the counters
6. When finished, click OK
For more information Performance Monitor, visit the Performance Monitor Getting Started Guide (http://technet.microsoft.com/en-us/library/dd744567(WS.10).aspx) on TechNet.

 Evaluate Hyper-V Replica log data using the Microsoft-Windows-Hyper-V-VMMS\Admin log

Virtual Machine - Primary Site
Management tasks involving virtual machines at the Primary Site include:
 Planned Failover - This action initiates a failover of a virtual machine from a Primary to a Replica server. This is a 'planned' event as opposed to a Failover action, which is unplanned. Since it is a 'planned' event, there should be no data loss. This action executes a series of checks prior to executing the failover. One check determines if the Primary server has also been configured as a Replica server. This is done because the assumptions are first, the virtual machine being failed over to a Replica server will eventually be moved back to the Primary server and second, the Primary server will become the Replica server for the virtual machine that is being failed over. This action provides an Administrator the flexibility to execute the failover of a virtual machine to a replica server in a controlled manner before a disaster occurs

To execute a Planned Failover for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine
3. With the virtual machine selected, Right-click and select Replication and then choose Planned Failover
4. A list of Pre-Requisites and Actions is presented. If the Virtual Machine has not been shut down and the Primary Server not configured as a Replica Server, complete those tasks before proceeding. By default, Start the replica virtual machine after Failover is checked (uncheck if this is not the desired action for the virtual machine after a Planned Failover completes)
5. Click on the Failover button.
6. If the Failover is successful, a pop-up dialog box appears reporting the Failover completed successfully (Note: If the option to start the virtual machine after the Planned Failover was left checked, then the virtual machine will be started on the Replica server). Close the dialog box.
7. If the Planned Failover does not complete successfully, review the information contained in the General Methodology for troubleshooting the virtual machine Failover process in the troubleshooting section.

 Pause Replication - This action pauses replication for the selected virtual machine. The Replication Health column in the Hyper-V Manager interface (if selected for display) reflects a Warning Status

To Pause Replication for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine that is not paused
3. With the virtual machine selected, Right-click and select Replication and then choose Pause Replication
4. The Replication Health, if visible, in Hyper-V Manager, will be updated and the Replication Health for the virtual machine will indicate a Warning. The State column still shows the Virtual Machine as Running
5. Right-click on the Virtual Machine, select Replication and then click on View Replication Health. The health report reflects an accurate Replication State which should be Replication Paused

 Resume Replication (Available only if replication has been paused for a virtual machine) - This action resumes replication for the selected virtual machine (the action must be executed in the same site where replication was Paused). The Hyper-V Replica Network Services component re-establishes a connection to the Replica server (if needed) and replication resumes. If the virtual machine was in a Resynch Required state, Resume Replication performs a resynchronization. A resynchronization essentially compares blocks between the Primary and Replica VHDs and then sends the delta blocks to the Replica. Scenarios where this can happen include, but may not be limited to, a failure occurred on the Primary server when changes were being made to the replication log or, if the Primary is a Failover Cluster, an unplanned cluster failover occurred. The Replication Health column in Hyper-V Manager interface (if selected for display) reflects a status of Normal

To Resume Replication for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a paused virtual machine
3. With the virtual machine selected, Right-click and select Replication and then choose Resume Replication
4. The Replication Health, if visible, in Hyper-V Manager, is updated and the Replication Health for the virtual machine is Normal

 View Replication Health - This action provides data about the replication events for a virtual machine.
A Replication Health Report can be saved as a CSV file. A Replication Health Report indicates if it is being viewed as either a Primary or a Replica virtual machine (see a sample of a Replication Health Report on a Replica virtual machine later in this guide)

To view Replication Health for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine
3. With the virtual machine selected, Right-click and select Replication and then choose View Replication Health
4. The Replication Health Report for the virtual machine is displayed. The report can be saved as a CSV file by clicking on Save as … Button

 Remove Replication - This action stops replication for the virtual machine. All connections for the virtual machine to the Replica server are terminated. The Replication Health in Hyper-V Manager on the Primary server, if selected for viewing, is Not Applicable. A corresponding action must be accomplished on the Replica server. Failure to execute this same action on the Replica server will result in errors should a Hyper-V Administrator attempt to re-enable replication for the virtual machine (more information is provided in the Troubleshooting section)

To Remove Replication for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine
3. With the virtual machine selected, Right-click and select Replication and choose Remove Replication
4. Acknowledge the pop-up Warning by clicking on Remove Replication
5. The Replication Health column, if displayed, indicates Not Applicable for the virtual machine
6. Connect to the Replica server and execute Steps 1-5. This will remove replication for the virtual machine on the Replica server and will initiate a merge for all the replica information for the virtual machine
7. The Replication Health column, if displayed, indicates Not Applicable for the virtual machine
8. Additional cleanup action is required on the Replica server. In Hyper-V Manager, Right-click on the virtual machine and choose Delete. Acknowledge the pop-up Warning by clicking on Delete. This removes the virtual machine reference in Hyper-V Manager. Some data files remain on the Replica server in the storage location specified for the replication data. To recover storage space, manually remove the data.

 Enable Replication (Available only if replication is not enabled for a virtual machine) - This action enables replication for a virtual machine

To Enable Replication for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine
3. With the virtual machine selected, Right-click and select Enable Replication
4. Review the information in the Before You Begin screen and click Next
5. In the Specify Replica Server screen, provide the name for the Replica Server using the Fully Qualified Domain Name (FQDN) or NetBIOS format. There is also the option to Browse Active Directory for the server. If the Replica Server is configured correctly, the Specify Connection Parameters screen is populated. If not, an error is registered and an option to Configure Server is available to configure the server to be a Replica Server. If data compression is not desired, Uncheck the box Compress the data that is transmitted over the network. Click Next
6. In the Choose Replication VHDs screen, ensure all disks to be replicated are Checked and then click Next (i.e. uncheck those disk you do not want replicated. An example might be a disk functioning as a repository for the virtual machine page file)
7. In the Configure Recovery History screen, select as desired. For an explanation of the options, review the section on Enabling a virtual machine for replication. Click Next
8. In the Choose Initial Replication Method screen, select as desired. For an explanation of the options, review the section on Enabling a virtual machine for replication. Click Next
9. Review the information in the Summary screen, and click Finish
Once replication has been enabled for a virtual machine, the Replication Health column, if visible, in Hyper-V Manager will be updated. Once the Initial Replication (IR) has been completed, the Replication Health for a virtual machine will be Normal.

Virtual Machine - Replica Site
Management tasks involving virtual machines at the Replica Site include:
 Failover - This action executes a process that starts a virtual machine on the Replica server using a replica (Recovery Point) selected by the Hyper-V Administrator. This is an unplanned event unlike the Planned Failover action, which is a planned event. Executing a Failover for a virtual machine could result in data loss depending on which recovery point is selected

To Failover a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine
3. With the virtual machine selected, Right-click and select Replication and then choose Failover
4. In the next screen, choose a recovery point from the drop-down listing of all the recovery points associated with the virtual machine and then click Failover
5. The virtual machine starts and the Replication Health indicates Warning. If the Primary server remains the same, the Replication Health for the virtual machine that was recovered is also Warning. To complete the process and remove the Warnings, either Cancel Failover or configure Reverse Replication and allow Initial Replication to complete. If a new Replica Server is needed, configure Reverse Replication to the new Replica server.

 Test Failover - This action allows a Hyper-V Administrator to test a virtual machine on the Replica server without interrupting the production workload running on the Primary server. The network configuration for the test virtual machine is disconnected by default so as not to interfere with the production workload. If network connectivity is to be tested, the recommendation is to create a separate test network and connect the test virtual machine to that network. The virtual machine created and started has the same name as the original virtual machine with a modifier of Test added on to the end

To start a Test Failover for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine
3. With the virtual machine selected, Right-click and select Replication and then choose Test Failover
4. In the next screen, choose a recovery point from the drop-down listing of all the recovery points associated with the virtual machine and then click Test Failover. A new test virtual machine is created but is not started. At this point, the virtual machine can be started and then a connection can be made to the virtual machine and a verification process can be completed

 Stop Test Failover (Available only if a test is already running for the selected virtual machine) - This action stops a test that is in progress for the selected virtual machine. The virtual machine is stopped and deleted from Hyper-V Manager (Note: If the Test Failover is being executed on a Replica cluster, the Test-Failover role that is created in Failover cluster Manager will have to be manually deleted)

To stop a Test Failover for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select the virtual machine being tested, not the test virtual machine that is running. Right-click on the virtual machine, select Replication and then choose Stop Test Failover
3. The test virtual machine is stopped if it is running and is removed from Hyper-V Manager as the test is completed

 Pause Replication - This action pauses replication for the selected virtual machine. The Replication Health column in Hyper-V Manager, if selected for viewing, indicates a Warning
To Pause Replication for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine that is not paused
3. With the virtual machine selected, Right-click and select Replication and then choose Pause Replication
4. The Replication Health, if visible, in Hyper-V Manager, is updated and indicates a Warning

 Resume Replication (Available only if replication has been paused for a virtual machine on the Replica server) - This action resumes replication for the selected virtual machine. If a 'resynch' is required for the virtual machine, that action will be initiated on the Primary server. The Replication State column, if selected for viewing in Hyper-V Manager, indicates Replication Enabled

To View Replication Health for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine
3. With the virtual machine selected, Right-click and select Replication and then choose View Replication Health
4. The Replication Health Report for the virtual machine is displayed. The report can be saved as a CSV file by clicking on Save as…
 Remove Replication - If a Remove Replication action is executed on the Replica server, a corresponding action must be executed on the Primary Server. This action stops replication for the virtual machine. Prior to re-enabling replication, the virtual machine must be deleted in Hyper-V Manager on the Replica server. This destroys the virtual machine on the Replica Server. If the virtual machine is not deleted, a Replication error is reflected in Hyper-V Manager and associated error logs are registered (more information is provided in the Troubleshooting section)

To Remove Replication for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine
3. With the virtual machine selected, Right-click and select Replication and then choose Remove Replication
4. Acknowledge the pop-up Warning by clicking on Remove Replication
5. The Replication Health column, if displayed, indicates Not Applicable
6. A process will start to merge all recovery point data into the VHD that was initially replicated
7. Connect to the Primary server. In Hyper-V Manager, the virtual machine Replication Health indicates Normal
8. Execute Steps 1-5. This removes replication for the virtual machine on the Primary server
9. The Replication Health column, if displayed, now indicates Not Applicable on the Primary server. If Step 8 is not accomplished before the next 5 minute replication interval, Replication Health will indicate Critical
10. Additional cleanup action is required on the Replica server. In Hyper-V Manager, Right-click on the virtual machine and choose Delete. Acknowledge the pop-up Warning by clicking on Delete. This removes the virtual machine reference in Hyper-V Manager. Some data files remain on the Replica server in the storage location specified for the virtual machine. To recover storage space, manually remove this data

 Cancel Failover - This action is available if a Failover action was executed for a virtual machine. This allows a Hyper-V Administrator to cancel the Failover action if, for example, he decides the recovery point chosen was not the desired one. After cancelling the Failover, another recovery point can be selected and another Failover process initiated. A Failover can only be cancelled if the virtual machine state is Failed over - Waiting Completion. If a Reverse Replication has been completed, the Failover can no longer be cancelled
To Cancel Failover for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine that has a Replication Health of Warning but viewing the Health Report shows Failover Complete
3. With the virtual machine selected, Right-click, select Replication and then choose Cancel Failover
4. Acknowledge the pop-up Warning by clicking on Yes. On the Replica server, the virtual machine is turned off and the Replication Health indicates Normal. On the Primary server, the Replication Health shows Critical.
5. To clear the Critical health state, right-click on the virtual machine and select Replication and then choose Resume Replication

 Reverse Replication - This action is available if a Failover action was executed for a virtual machine. This allows the Hyper-V Administrator to designate a Hyper-V server as a Replica server for the virtual machine that was recovered

To enable Reverse Replication for a virtual machine:
1. Open Hyper-V Manager
2. In the details pane, select a virtual machine that has a Health of Warning
3. With the virtual machine selected, Right-click, select Replication, and then choose Remove Recovery Points. This merges all the recovery points into the original VHD. This completes Failover but Replication Health still indicates Warning
4. With the virtual machine selected, Right-click, select Reverse Replication
5. Complete the Reverse Replication wizard by either selecting the Primary server (the default) as the Replica y server or choosing another Replica server. Keep in mind that if the selected Hyper-V server has not been enabled as a Replica server and the appropriate firewall rule enabled, the Reverse Replication process will fail

 Remove Recovery Points - This action is available only during a Failover scenario. When this action is executed, all recovery points (snapshots) for a Replica virtual machine are deleted. When the action is executed, a pop-up dialog box is presented to the user indicating all recovery points will be removed and Cancel Failover will no longer be available. The user must acknowledge the pop-up by clicking either Yes or No. If Yes is selected, the Failover is committed and the recovery points are merged down into the base VHD for the virtual machine. At this point Reverse Replication can be configured to clear the Warning for Replication Health and an Initial Replication can begin to the new Replica Server

Disclosure: My company does not have a business relationship with this vendor other than being a customer.

it_user2652Project Manager at a non-tech company with 10,001+ employees

Report as inappropriate

Oct 20, 2013

Thanks for the excellent review on Hyper-V. Just wanted to know if there is any limit of hosts on hyper-V? What external monitoring tool do you recommend for monitoring hyper-v servers?

it_user9222

Engineer at a outsourcing company with 51-200 employees

Oct 2, 2013

Hyper-V 2008 – VMs Show Host MAC Address In ARP Cache

Recently while working with a customer that was migrating from Hyper-V 2008 R2 to Hyper-V 2012, I came across an issue where VMs on the original host were having odd intermittent network connectivity issues. As I dug into the problem, I realized that when I ran arp -a on any of the Hyper-V hosts, VMs on the original host were showing up in the ARP cache with a MAC address of the physical host, instead of their virtual MAC address.

As it turned out, it was the drivers for the Broadcom NICs in this particular system. Windows Server 2008 does not support NIC teaming natively, and instead relies on the 3rd party drivers to support teaming. Due to a bug in some versions – possibly all, I have not been able to confirm this as of yet – of the Broadcom drivers, Hyper-V 2008 hosts using a Broadcom teamed interface will advertise the hosts’s MAC address to the physical switch rather than the VM’s virtual MAC.

The workaround was to break the team, and only use one physical interface during the migration to 2012. This resolved the MAC issues, and since Windows/ / Hyper-V 2012 supports native NIC teaming, the issue did not occur on the new hosts.

Disclosure: The company I work for is partners with several vendors - http://www.latisys.com/partners/strategic_partnerships.html

Disclosure: My company does not have a business relationship with this vendor other than being a customer.