Virtualization showdown: Microsoft Hyper-V 2012 vs. VMware vSphere 5.1

[ Editor’s note: This article has been revised to underscore the fact that we tested VMware vSphere with vCenter Server but we tested Windows Server 2012 Hyper-V without System Center 2012, and therefore these reviews do not constitute a straightforward comparison. ]

Any comparison of Microsoft’s Hyper-V versus VMware’s vSphere has to take into consideration a number of different factors. First, there’s the target customer and the features required for different sizes of deployments. The needs vary widely depending on the number of virtual machine instances, and these requirements will drive the architecture and configuration choices. Second, there is the topic of management, which is also tied closely to the size of the installation. Beyond these considerations are a number of other issues, including cost, performance, scalability, and usability.

It was once a truism that Microsoft’s solution was for small shops and VMware’s was for large deployments, but that is no longer the case. VMware has plenty to offer small shops, and Microsoft has the features to compete at the high end. Microsoft and VMware both make it easy to start small and add capabilities as your virtualization environment grows. But they take different paths to this goal.

True to form, Microsoft bundles the full gamut of virtualization capabilities into the operating system. With Windows Server 2012, or the free Hyper-V Server 2012, you can create high-availability Hyper-V clusters and tap advanced features such as live VM and storage migration, VM replication, and even network virtualization. As the numbers of hosts and VMs grow, you can beef up the management and automation capabilities by deploying System Center 2012.

By contrast, VMware vSphere includes the central management system, vCenter Server, as part of the deal. While you can virtualize servers to your heart’s content using the free VMware ESXi hypervisor, the vCenter Server is needed to implement high-availability and unlock features such as live migration, replication, and the distributed virtual switch. These capabilities and more are available on a sliding scale as you move up the ladder of vSphere editions.

Targeting the small business customer
 No matter how big or small your environment is, your number one priority will be to keep your servers running. High availability (HA) — which involves detecting when a physical host is down and rebooting its guest VMs on another host — is a capability that will matter to shops of any size. Both Microsoft and VMware put HA within a small shop’s reach.

The ability to create high-availability host clusters is not only provided in both Windows Server 2012 Hyper-V and the free Hyper-V Server 2012, but Hyper-V can now leverage new capabilities in SMB 3.0 that give even the smallest shops the ability to stand up an HA cluster using low-cost servers and commodity SAS disk drives. You no longer need a Fibre Channel or iSCSI SAN.

With Windows Server 2012, Microsoft also introduces Hyper-V Replica. Hyper-V Replica provides unlimited host-to-host replication of virtual machines without shared storage. In other words, you don’t need clustering but you can replicate to a cluster if you have one. Enabling replication is simple, and it’s fully configurable from the Hyper-V Manager client.

VMware brings high availability to small shops with the vSphere Essentials Plus edition, which lets you create an HA cluster of three hosts. For those wanting to skirt the costs of an expensive SAN or NAS, Essentials Plus includes the vSphere Storage Appliance (VSA), software that allows you to implement HA by turning the internal storage of three vSphere hosts into a single, redundant, shared storage pool. Essentials Plus also includes host-to-host VM replication.

Nearly as important as high availability itself is live VM migration. The ability to move running virtual machines from host to host, without disrupting applications and users, live migration can mean the difference between uptime and downtime when the time comes for hardware maintenance or upgrades.

By automating live migrations based on resource consumption and thresholds, you can effectively balance the VM workload across all of your virtualization hosts. This is a feature that becomes important as you increase the number of hosts and the number of VMs per host. Automated VM load balancing is available in VMware’s Enterprise and Enterprise Plus editions, and it requires System Center 2012 to be implemented with Hyper-V. VMware can also automate workload balancing across multiple storage devices; storage load balancing is available only in the Enterprise Plus edition.

Management tools In our reviews of Windows Server 2012 Hyper-V and VMware vSphere 5.1, we tested vSphere together with vCenter Server (naturally) but Windows Server 2012 Hyper-V without System Center 2012. We didn’t examine the higher-end management and automation tools, but instead focused on the management tools that smaller shops would rely on.

At the low end, Microsoft gives you a basic set of tools in Hyper-V Manager, which comes as an installable option with Windows Server 2012. VMware’s traditional management tool, the VMware vSphere Client, is a free client you must install on a Windows PC. Both offerings connect to remote hosts, allowing you to manage any system you can reach over the network.

Some functions are not possible in the basic management tools for either product. Advantage here goes to Microsoft as Hyper-V Manager can, for example, export a VM, then do an import to clone or copy the VM. With VMware you must be connected to vCenter Server in order to export or clone a VM. With respect to monitoring, however, the VMware vSphere Client provides much more information about both the host servers and the client VMs. VMware scores a point here for a more detailed graphical presentation.

The latest release of vCenter Server (5.1) adds a Web client to the mix, providing the ability to manage your VMware infrastructure from literally anywhere. Both VMware and Microsoft support automated management using Windows PowerShell. VMware offers a free add-on called PowerCLI that includes a long list of custom PowerShell cmdlets for managing your vSphere infrastructure.

Performance and scalability Deciding how to measure performance and scalability presents a challenge when comparing these two products. Microsoft has made a number of enhancements in Hyper-V 2012 that in some cases exceed the outer limits of vSphere. If you want to gauge scalability in terms of raw numbers like nodes supported in a cluster (64 for Hyper-V 2012 vs. 32 for vSphere 5.1) or VMs in a cluster (8,000 for Hyper-V 2012 vs. 4,000 for vSphere 5.1), you would deduce that Microsoft has the more scalable solution.

But measuring real-world capacity goes way beyond the basic numbers. Case in point: Both products now support the concept of dynamic memory management, albeit in different manners. With Hyper-V 2012, you can configure individual VMs with an initial memory allocation and allow the hypervisor to adjust the amount of memory depending on current needs. This is not the default option when creating a new VM but a configuration setting. VMware has had dynamic memory management for several years, and unlike Microsoft, its memory management applies to all guest operating systems, not just Windows.

At the individual VM level, we used the Sandra 2013 benchmarking tool to determine basic numbers of performance from a single VM running Windows 7 SP1. This VM was configured to have 2GB of memory and two virtual CPUs. We ran four different benchmarks using Hyper-V 2008, Hyper-V 2012, vSphere 5.0, and vSphere 5.1. You can see from the table that Hyper-V 2012 performed better than vSphere, at least with respect to running Windows VMs. Note that we did not test the hypervisor under load or the performance of Linux VMs, as was done in InfoWorld’s 2011 virtualization shootout. (Tests were run on a Dell PowerEdge R715 with dual AMD Opteron 6380 CPUs, 64GB of memory, and two Seagate ST9300605SS 10K 300GB SAS drives configured as a RAID1 array.)

The bottom line Finally, one of the most difficult factors to compare is cost. If you’re looking at a small number of virtualized servers running Windows Server 2012, you already get that with the purchase of the operating system. Windows Server 2012 Standard comes with two virtual instances, while Windows Server 2012 Datacenter includes an unlimited number of VMs on a single machine. If you’re already investing in Windows Server 2012, it may not make sense to purchase an additional virtualization product for a small-to-medium deployment.

That said, if you are starting small and planning to scale out your virtualization farm significantly over time, VMware could present a smoother growth path. The vCenter Server is easily deployed as a virtual appliance, and it serves as a single, central provider of every vSphere management capability — host provisioning and configuration management, VM templating and cloning, health and performance monitoring, automated load balancing of VMs and storage, etc.

By contrast, the management capabilities of System Center 2012 span multiple tools and repositories. These start with Virtual Machine Manager (VMM) — for managing Hyper-V hosts, clusters, and virtual machines — and extend to Operations Manager (which integrates with VMM to automate load balancing and provide health and performance monitoring), Configuration Manager, Data Protection Manager, Orchestrator, and App Controller.

On one hand, the abundance of System Center components increases the management overhead and complexity, in comparison to vCenter Server. On the other hand, if the goal is to virtualize a primarily Windows-based infrastructure (and it usually is), then all of those System Center tools may be needed to manage your Windows servers and Microsoft applications anyway.

And this raises an important point made by IDC’s Al Gillen, the industry research firm’s analyst on operating systems, cloud, and virtualization: The VMware and Microsoft stacks are not mutually exclusive.

“Let’s say you’re a big VMware shop,” Gillen says. “The reality is you probably still need System Center to manage your Windows servers. So it’s not really an apples to apples comparison.” At the same time, he notes, shops are much more likely to use multiple hypervisors today than they were in the past.

You can certainly go much further with Microsoft’s free hypervisor than you can with VMware’s. At the top of the value chain, VMware still has some capabilities that Microsoft can’t match. In between, the choice between Microsoft and VMware has never been harder. And that’s great news for the customers.

Read the reviews:

• Microsoft Hyper-V 2012 narrows the gap
• VMware vSphere 5.1 looms large

This article, “Virtualization showdown: Microsoft Hyper-V 2012 vs. VMware vSphere 5.1,” was originally published at InfoWorld.com. Follow the latest developments in virtualization, data center, and cloud computing at InfoWorld.com. For the latest business technology news, follow InfoWorld.com on Twitter.