Overview of Server Virtualization with Windows Server 2012 R2

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Windows Server Hyper-V is a sophisticated and feature-rich virtualization platform that has helped organizations of all sizes realize considerable cost savings and operational efficiencies. With Windows Server 2012 R2, server virtualization with Hyper-V is pulling ahead of the competition with industry leading size and scale, making Hyper-V the platform of choice for you to run your mission critical workloads.

Whether you are looking to expand VM mobility, increase VM availability, handle multi-tenant environments, gain bigger scale, or gain more flexibility, Windows Server 2012 R2 with Hyper-V gives you the platform and tools you need to increase business agility with confidence. And you can benefit from complete workload portability as you extend your on-premises datacenter into the cloud to a service provider cloud or Windows Azure.

Enterprise-class scale and performance

Windows Server 2012 R2 provides you with massive scale to transform your datacenter into an elastic, always-on cloud. For example, Hyper-V in Windows Server 2012 R2 provides industry-leading virtualization host support for 320 logical processors, 4TB of physical memory and 1,024 active virtual machines per host. Hyper-V supports 64-node clusters and 8,000 VMs per cluster. And it supports a 64 TB virtual disk format with the ability for online resize, i.e. the ability to grow or shrink a VHDX virtual disk dynamically while it is running, and with no downtime.

Live migration is an important VM mobility feature that has kept getting better and better with Hyper-V since it was introduced with Windows Server 2008 R2. Improving the performance of live migrating a VM from the source host to the target host has been a constant focus for Windows Server, and in Windows Server 2012 R2 these performance improvements have been taken to the next level:

  • Live migration compression is a new feature that accelerates live migration transfer speed by compressing the VHD/VHDX file, improving performance roughly by 2x for most workloads.
  • Live migration with RDMA is another new feature in Windows Server 2012 R2; it delivers the highest performance for live migrations over >10 Gbit network connections, supporting transfer speeds of up to 56 GB/s, by offloading the transfer to hardware and harnessing the power of remote direct memory access (RDMA) technologies.

Virtualized Microsoft workloads (such as Exchange, SQL, and SharePoint) run best on Hyper-V infrastructure.

For example, independent third party testing by The Enterprise Strategy Group, Inc. (“ESG Lab”) showed that a Microsoft Exchange Server 2013 infrastructure deployed within twelve Hyper-V virtual machines, running on a single physical server, supported the I/O requirements of up to 48,000 simulated users, while average database read response times ranged between 5.02 and 15.31 milliseconds, well below the Microsoft recommended limit of 20 milliseconds. In another test case, ESG Lab took an existing Microsoft SQL Server 2012 OLTP workload that was vCPU limited by the maximum allowed configuration of four vCPUs imposed by Windows Server 2008 and increased the performance by six times taking advantage of 64 vCPUs in Windows Server 2012. The average transaction response times also improved by five times from four vCPUs to 64 vCPUs.

Virtual machine mobility

Windows Server 2012 R2 allows you to manage virtual machines independently of their underlying physical infrastructure. It also enables you to handle changes in resource demand as they occur and gives you the ability to rebalance running virtual machines either through the servers which the VMs reside on, or the storage resources used by the virtual machines.

Introduced with Windows Server 2012 as an industry-first capability, shared-nothing live migration allows you to move a virtual machine, live with no downtime, from one physical system to another even if they are not in the same cluster or connected to the same shared storage. This capability means you can live migrate a virtual machine from one cluster to a different cluster without setting up complex storage mappings. This is useful, for example, in a branch office where you may be storing the virtual machines on local disk, and you want to move a VM from one node to another. This is also especially useful when you have two independent clusters and you want to move a virtual machine, live, between them, without having to expose their shared storage to one another.

You can also use shared-nothing live migration to migrate a virtual machine from one datacenter to another provided your bandwidth is large enough to transfer all of the data between the two datacenters.

In multi-tenant environments of service providers, tenants are more and more asking for application-level, high availability for their workloads. To address this need, Windows Server 2012 R2 provides complete flexibility with multiple options for guest clustering, without making you sacrifice agility and density in your environment.

In addition to Fibre Channel, iSCSI and SMB, Windows Server 2012 R2 now also offers shared VHDX files. Supporting both storage options, shared VHDX files can be stored either on a scale-out file server cluster or on Cluster-shared Volumes (CSV) on block storage. Shared VHDX clustering also preserves dynamic memory, live migration and storage live migration for a virtual machine that is part of the guest cluster.

Introduced in Windows Server 2012 R2, Hyper-V Replica provides a storage-agnostic and workload-agnostic solution that replicates efficiently, periodically, and asynchronously over IP-based networks, typically to a remote site. It also allows an administrator to easily test the replica virtual machine without disrupting the ongoing replication. If a disaster occurs at the primary site, administrators can quickly restore their business operations by bringing up the replicated virtual machine at the replica site. New in Windows Server 2012 R2, Hyper-V Replica now allows for variable (configurable) replication frequencies down to 30 seconds or up to 15 minutes. It also supports multiple nodes; this means that tertiary replica sites are supported, for example in the case of a service provider who wants to replicate a customer’s workload to another (tertiary) datacenter.

Improvement on guest support for Linux

Many enterprises and service providers are running a mix of hypervisors, operating systems and applications in their datacenter. Often times, migrating from one platform to another is not possible, not easily feasible from a technical standpoint, or a much bigger project than IT organizations are willing to take on. Designed to integrate well with heterogeneous IT environments, Windows Server 2012 R2 supports a cross-platform cloud infrastructure by adding comprehensive functional support for Linux guests running on top of Hyper-V.

Dynamic Memory is a Hyper-V feature that was introduced with Windows Server 2008 R2 SP1 and is used to automatically reallocate memory between virtual machines that are running on a Hyper-V host. Dynamic Memory helps you to allocate virtual machine memory resources more efficiently while dramatically increasing virtual machine consolidation ratios. A number of improvements were made for Windows guests in Windows Server 2012, and – new in Windows Server 2012 R2 – Hyper-V now offers full dynamic memory support for Linux guests including:

  • Minimum memory setting – being able to set a minimum value for the memory assigned to a virtual machine that is lower than the startup memory setting
  • Hyper-V smart paging – which is paging that is used to enable a virtual machine to reboot while the Hyper-V host is under extreme memory pressure
  • Memory ballooning – the technique used to reclaim unused memory from a virtual machine to be given to another virtual machine that has memory needs
  • Runtime configuration – the ability to adjust the minimum memory setting and the maximum memory configuration setting on the fly while the virtual machine is running without requiring a reboot.

Also, up until now, if you wanted to take advantage of Linux Integration Services (LIS) for your Hyper-V environment, you had to go to the Microsoft download center, download the correct LIS package for your Linux distribution, and then manually install it on your Hyper-V servers. New for Windows Server 2012 R2 Hyper-V hosts, key Linux vendors (such as RHEL, SUSE, CentOS and Ubuntu) are going to include LIS for Hyper-V in their standard distributions, so there is no manual step involved any longer in order for you to take advantage of the latest LIS capabilities.


Marcos Nogueira
Twitter: @mdnoga

Written by Marcos Nogueira

With more than 17 years’ experience in Datacenter Architectures, Marcos Nogueira is currently working as a Chief Technology Officer at NogaIT Consulting. He is an expert in Private and Hybrid Cloud, with a focus on Virtualization, System Center and Microsoft Azure. He has worked in several industries, including Aerospace, Transportation, Energy, Manufacturing, Financial Services, Government, Health Care, Telecoms, IT Services, and Gas & Oil in different countries and continents.

Marcos is an MVP in Hyper-V and he has +12 years as Microsoft Certified, with more than 80+ certifications (MCT, MCSE, and MCITP, among others). Marcos is also certified in VMware, CompTIA and ITIL v3. He assisted Microsoft in the development of workshops and special events on Private Cloud, System Center, Windows Server, Hyper-V and as a speaker at several Microsoft TechEd and communities events around the world.