VMware ESXi vs. Hyper-V Server

Greg Shields

Seven clicks. That's all it takes to install Microsoft's new Hyper-V Server to a candidate host. Seven clicks to deploy this direct competitor to VMware's ESXi appliance. Hyper-V Server is a free, recently released download from Microsoft that

    Requires Free Membership to View

brings free virtualization hosting to small environments, as well as to those that don't want to pay the extra cost of ESXi.

So while Microsoft requires no server license and no client access license (CAL) for a Hyper-V Server installation, the question remains how does it stack up to VMware's Operating System-less equivalent? In this article I'll cover the installation of Hyper-V Server and also discuss some of the advantages it can provide users over VMware ESXi.

Installing Hyper-V Server
Hyper-V Server arrives as an ISO file that is intended to be burned to physical media. Booting a candidate virtual host with the media installs Hyper-V Server with a WinPE installation routine which is similar to that used for a typical installation of Windows Server 2008. Upon completing the installation, what you get is essentially an instance of Windows Server Core with the Hyper-V role already preinstalled.

When you log in for the first time, you'll be greeted with the same black background command prompt common to all Server Core instances. However Hyper-V Server adds a second blue background command menu. This secondary menu makes the initial server configuration quite a bit easier than what you're used to seeing with traditional Server Core. The blue window provides a menu-driven interface for setting the server's name and domain, networking information, Windows update configuration and other minor elements like regional/language options and date/time.

Any additional configurations that are not part of the blue menu can be done by entering commands into the black command prompt. This is, after all, a Windows instance. Many of the commands you're used to using with regular Windows will function inside Hyper-V Server's quasi-appliance installation.

Once the server's initial configuration is complete, there's very little left to do with the console itself. The management of the Hyper-V role is executed through the remote Hyper-V Manager, which is consolidated with the Microsoft Management Console (MMC), currently available only on Windows Vista SP1 and Windows Server 2008.

If you're familiar with the Hyper-V Manager console, then managing Hyper-V Server will be fairly simple. You'll want to identify and configure your network interfaces by first using the Virtual Network Manager, followed by adjusting any Hyper-V settings such as the location to store virtual hard disks and virtual machines (VMs).

The advantages of Hyper-V Server over VMware ESXi
One particular administrative boon of Hyper-V Manager over ESXi is its use of NTFS partitions for the storage of VMs as opposed to VMware's proprietary VMFS. Hyper-V Server can support the hosting of virtual machines through virtually all forms of Direct-Attached Storage and Network-Attached Storage, in addition to traditional SAN storage via iSCSI, SAS, and Fibre Channel. Since Hyper-V Manager runs atop Server Core, whatever storage back-end you select must have client-side support for this special operating system version.

Although Hyper-V Server's signature is significantly larger than ESXi's (again, due to its reliance on its Server Core primary partition), that primary partition can be configured and otherwise managed through the same command line and remote console interfaces used to manage other Server Core instances. PowerShell cmdlets initiated from a management workstation can similarly read and write configurations as well. This may be of particular use to environments that have shied away from ESXi due to its severe limitations on customization.

ESXi can arguably be considered more of an "appliance" solution to virtual machine hosting than Hyper-V Server as is evident by its tiny 32 megabyte size. Hyper-V Server is a little less than one gigabyte in size, the vast majority of which is required for its Server Core underpinnings.

Unfortunately though there's only so much you can get for free, so Hyper-V Server doesn't arrive without its limitations. While it can be managed through Microsoft's System Center Virtual Machine Manager, in addition to the Hyper-V Manager console, it does not support host clustering. Microsoft has also removed most roles, role services, and features providing only eight installable components through Server Core's ocsetup.exe installation routine: BitLocker and its remote administration tool, removable storage management, multipath IO, network load balancing, simple network management protocol (SNMP), the telnet client and Windows Server Backup.

As a major advantage to environments who value application crash consistency in their backups, Hyper-V Server natively supports volume snapshot service (VSS) integration. This capability, not yet available in ESXi, enables resident virtual machines to be properly quiesced before they are backed up. This integration ensures that VSS-aware applications, in addition to the file system, are backed up correctly.

In the end, Hyper-V Server is a compelling product for Microsoft as they vie for the market share in SMB and mid-market companies. These companies may not yet find the return on investment (ROI) for virtualization solutions very compelling and may be rightfully intimidated by VMware's roots in the Linux operating system. For admins that desire a bit more control over the configuration of their virtualization hosts, Hyper-V Server may be a compelling alternative to VMware ESXi's all-appliance solution.

This story first appeared at