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VMware to Hyper-V converts share lessons learned

Users making the switch from VMware to Hyper-V say they’ll save on licensing costs, but migration plans can be stymied by Linux VM migrations and long-term licensing agreements.

Some IT pros will move from VMware to Hyper-V when new virtualization management tools in Microsoft’s System Center 2012 and a new version of Hyper-V hit later this year.

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Though switching hypervisors can be a challenge, some say that the cost savings make it a worthwhile move.

One VMware shop based in Chicago will move the last VMware holdouts in its virtualization environment to Hyper-V when Windows Server 2012 becomes available. The Walsh Group, a contractor and construction management company, will save $150,000 per year in slashed VMware Inc. licensing and staffing costs by switching to Microsoft Hyper-V, estimated Patrick Wirtz, manager of technology innovation.

The company, which spreads its IT services between a main data center in Chicago and 100 to 150 remote job sites, will also add automation to its environment with System Center 2012.

Meanwhile, about 20% of the environment -- including a mission-critical ERP application in the data center and some of the servers at remote job sites -- remain on VMware, at least for now. The company will move the ERP app to Hyper-V as part of an application upgrade, Wirtz said, but only when Windows Server 2012 Hyper-V supports more virtual CPUs (vCPUs) per virtual machine (VM).

In the developer preview released last fall, Microsoft said each guest can support up to 32 vCPUs and 512 GB of memory, up from a limit of 4 vCPUs and 8 GB of RAM.

 “Being able to allocate those extra CPU cores to mission-critical apps, like our financial system, is really key for us,” Wirtz said.

Another new Hyper-V feature, shared-nothing live migration, will help the company migrate off VMware at remote job sites where there is only one server, Wirtz added., an online real estate search engine headquartered in Chicago, began its move from VMware to Hyper-V last year. The company, a heavy-duty Microsoft Windows Server shop, found that Hyper-V licensing costs less than VMware vSphere licensing and it will gain the private cloud features in System Center 2012. In addition, Microsoft tools used by its developers, such as Visual Studio and Team Foundation Server (TFS), are better integrated with Hyper-V.

“When we had VMware in the house, I had to have … Windows server gurus and VMware gurus,” said Matt Stratton, director of technology operations. “It’s a different skill set to hire for.”

VMware vSphere to Hyper-V migration hurdles’s dev / test data center was migrated first, beginning in November and ending in early December. About 170 Windows VMs were migrated automatically through System Center Virtual Machine Manager (SCVMM) 2008 R2, but Stratton said his team encountered a hang-up when it went to convert about 40 Linux VMs using the same process.

“We found that the migration tool in VMM was using [SSH File Transfer Protocol] to migrate the VM and the connection was so slow as to continually time out,” Stratton said. Instead, the team manually copied each Linux VM’s VMware VMDK file, converted it to Microsoft’s Virtual Hard Disk (VHD) format, and then attached it to a new VM in SCVMM.

As moved its production VMs, it discovered the importance of having Microsoft’s Linux integration components installed on Hyper-V. Not having these can cause clock skew between host and VM, for example. “Lesson learned,” Stratton said.

Hyper-V and VMware network configurations also differ. Hyper-V requires a dedicated Live Migration interface separate from the management interface. In the previous VMware configuration, the company ran management and vMotion on the same virtual local area network across two network interface cards (NICs) set for active/passive failover. Because Hyper-V does not support this, more NICs are required per physical server.

“That said, this is probably more of a case of VMware letting us get away with a less than optimal configuration, and we were unable to reproduce it in Hyper-V,” Stratton said. Microsoft’s lack of support for direct connection to Fibre Channel storage in the current version of Hyper-V also presented a problem for Stratton. Until Windows Server 2012 is released later this year, this type of connection is only supported on iSCSI storage, and Stratton’s only workaround has been to convert the VMs that required a direct connection to Fibre Channel storage back to physical machines.

“Was it the end of the world? No, but we don’t like having to do that,” he said.

Microsoft did not respond to a request for comment regarding those problems.

Long-term licensing makes VMware sticky
Some VMware users are sold on Hyper-V, but are unable to make the migration because of long-term licensing commitments.

Cost savings are king in the world of public education, according to Brian Hatchell, network manager for Victor Valley College, a community college in Victorville, Calif. All the community colleges in California buy as one unit, and get discounts from Microsoft on enterprise licenses, including Hyper-V. Hatchell estimates the cost savings of going with Hyper-V at anywhere from $80,000 to $100,000 per year.

“That will be very useful in expanding wireless or buying more storage or many things we’re going to have to do,” he said. “If I had unlimited budget, I would probably prefer to stay with VMware. But if it does the job, it does the job, that’s the way we look at it around here.”

Hatchell still has about three years to think about it -- that’s how much is left on the five-year licensing agreement he signed with VMware.

Heterogeneous virtualization management eases hypervisor transitions
Meanwhile, companies that run both VMware and Microsoft Hyper-V have ways to manage both environments.

Hatchell uses SolarWinds Server Virtualization Manager for both VMware and Hyper-V, which he runs in his test environment. During a migration between VMware and Hyper-V, the tool will allow him to see performance statistics in real time, so he will know how many VMware VMs he can load onto each Hyper-V host.

Microsoft’s SCVMM 2012 serves as a similar centralized point of heterogeneous virtualization management in Wirtz’s shop.

Beth Pariseau is a senior news writer for and Write to her at

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