10 great new features in Windows Server 2012 R2 Hyper-V …. ( You know you want to know )
Apr 19, 2014

I often get asked by students and clients which I like better, VMware or Hyper-V?

I try to frame the response to such questions in even handed terms, and not to get hung up on the ” this is better in this product ” kind of comparisons, as these conversations generally, and very quickly, devolve into a discourse on why I am wrong, and why the chosen favorite of the person asking my opinion in the first place is soooooo much  better because ……

Up until the release of Windows Server 2008, and more importantly, Windows Server 2008 R2, it was hard to make the case that Hyper-V was up to the task of going head to head with VMware. Personal preferences aside for platforms, it was just not as mature a technology as it needed to be. Starting with 2008 R2 and certainly with the arrival of Windows Server 2012, and now 2012 R2, that is not the case any longer.

You may have your favorites, and that is perfectly acceptable by the way, as long as you keep them to yourself unless asked, but regardless of vendor chosen, it is hard not to get excited by all of the new features that both platforms have put on the table recently with their releases.

Below is my Top 10 for HyperV on Server 2012 R2, take a look and see if you find some things that you like.


Gen2 VM’s:

Hyper-V in Windows Server 2012 R2 supports the concept of a totally new architecture based on modern hardware with no emulated devices. This makes it possible to add a number of new features, such as secure boot for VMs and booting off of virtual SCSI or virtual network adapters. The catch is that guest support is limited to 64-bit versions of Windows 8 and Windows Server 2012.

 Gen2 VMs


VM Direct Connect:

Connecting to a running VM over RDP requires an active network connection. In addition to an active network connection, the VM must have an IP address reachable by the system attempting to connect, a requirement with potential management and security issues depending on the environment in which you are running. All this changes in Windows Server 2012 R2 and Hyper-V with the addition of VM Direct Connect. This feature allows a direct remote desktop connection to any running VM over what’s now called the VM bus. It’s also integrated into the Hyper-V management experience.


Extended Replication to a Third Site:

Hyper-V Replica in Windows Server 2012 is currently limited to a single replication target. This makes it difficult to support scenarios like a service provider wanting to act both as a target for a customer to replicate and a source to replicate to another offsite facility. Windows Server 2012 R2 and Hyper-V now provide a tertiary replication capability to support just such a scenario. By the same token, enterprises can now save one replica in-house and push a second replica off-site.

Extended Replication to a third site in HyperV 2012 R2


Replica Frequency Options :

Hyper-V Replica in Windows Server 2012 provides a fixed replication interval of 5 minutes. This means you cannot replicate any faster, even if you have the hardware to support it. Nor can you replicate any slower, even if you do not need such frequent copies. Two new options have been added in the Windows Server 2012 R2 release to support more frequent (30 seconds) and not so frequent (15 minutes) replication. This will even support an intermittent connection. By default, Hyper-V Replica will look for 12 missed cycles before it switches into a failed state. With the 15-minute cycle, you buy up to three hours of network downtime.

Configure Replication Frequency


Compression for Faster Migration :

Two new options in Windows Server 2012 R2 Hyper-V help improve the performance of live migrations. The first is the ability to enable compression on the data to reduce the total number of bytes transmitted over the wire. The obvious caveat is that tapping CPU resources for data compression could potentially impact other operations, so you will need to take that into consideration. The second option, SMB Direct, requires network adapters that support RDMA. Microsoft’s advice: If you have 10Gb available, use RDMA (10x improvement); otherwise, use compression (2x improvement). Compression is the default choice and it works for the large majority of use cases.

Compression for faster migration


Online VM Exporting & Cloning :

One of the downsides of Hyper-V in Windows Server 2012 is the need to stop a running VM before you can export or clone it. In production environments, this is simply not an option. Windows Server 2012 R2 Hyper-V removes this restriction. It’s now possible to export or clone a running VM from System Center Virtual Machine Manager 2012 R2 with a few mouse clicks. You can also accomplish the same task using Windows PowerShell.

Online VM Exporting & Cloning


Online VHDX Resizing :

In Windows Server 2012 Hyper-V, it is not possible to resize a virtual hard disk attached to a running VM. Windows Server 2012 R2 removes this restriction, making it possible to not only expand but even reduce the size of the virtual disk (VHDX format only) without stopping the running VM. What you cannot do with this feature: Compress an online VHD. You can make these adjustments from System Center Virtual Machine Manager 2012 R2, Hyper-V Manager, or the command line using PowerShell. You can use PowerShell to set the disk size to the current disk consumption if you want to reduce it to the absolute minimum.

Online VHDX resizing


Storage QOS :

Windows Server 2012 R2 includes the ability to limit individual VMs to a specific level of I/O throughput. In the screenshot below, you can see the two settings for minimum and maximum IOPS. The only number that really makes a difference is the maximum limit. The IOPS are measured by monitoring the actual disk rate to and from the attached virtual hard drives. If you have applications capable of consuming large amounts of I/O, you will want to consider this setting to ensure that a single I/O-hungry VM won’t starve neighbor VMs or take down the entire host.

Storage QOS


Dynamic Memory Support for Linux :

Microsoft continues to improve support for Linux VMs. In the Windows Server 2012 R2 release, Hyper-V gains the ability to dynamically expand the amount of memory available to a running VM. This capability is especially handy for any Linux workload where the amount of memory needed by the VM changes over time. In environments with many Linux VMs, dynamic memory becomes even more critical to efficiently manage the total memory used by all running VMs. Windows Server 2012 R2 Hyper-V also brings Windows Server backups to Linux guests.

Dynamic memory support for linux


Shared VHDX :

With Windows Server R2 Hyper-V, Windows guest clusters (think traditional Windows Server failover clustering but using a pair of VMs) no longer require an iSCSI or Fibre Channel SAN, but can be configured using commodity storage: namely a shared VHDX file stored on a Cluster Shared Volume. Note that while the clustered VMs can be live migrated as per usual, a live storage migration of the VHDX file requires one of the cluster nodes to be taken offline.

Shared VHDX





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