For some Microsoft Hyper-V virtualization users, Live Migration is no big deal. For others, it can't come soon enough.
Nissan North America implemented Windows Server 2008 with Hyper-V last year, reducing the number of servers at its Smyrna and Decherd, Tenn., plants from 159 to 28, eight of which run Hyper-V. At the same time, the team is actively testing Hyper-V R2 with Live Migration and will put it into production "as soon as we're comfortable with it," said Phil D'Antonio, Nissan's manager of conveyors and controls engineering.
Live Migration will give Nissan "the ability to migrate parts of our system without taking the server down, so we can repair the system, apply a patch or whatever without any downtime," said Matt Slipher, a systems engineer at the automaker.
The team now uses Hyper-V's "Quick Migration" feature to move virtual machines (VMs) off a Hyper-V host, a process which takes the system down for about 30 seconds while it gets rebooted on another host.
Thirty seconds may not sound like a lot, but it's actually a big deal, said D'Antonio. "These are manufacturing-related apps controlling movement of cars through the plant. If a server goes down, the plant stops. And once that happens, "a lot of testing has to happen" before systems can be brought back up and work can resume.
"Thirty seconds doesn't equal 30 seconds," D'Antonio said. "It could be 10 or 15 minutes" of lost production time for the plant.
As a result, Nissan's IT team currently does most of its planned maintenance "off shift" or during bi-annual plant shut-downs over Christmas and the summer months. "We just can't take the risk that something isn't going to come back up," D'Antonio said.
Slipher emphasized that Live Migration isn't any easier to use than Quick Migration; they're both integrated in to the management console. ""Live Migration isn't any easier -- it's the same -- but it doesn't take the system down," he said.Why not VMware or XenServer?
When Nissan began evaluating Hyper-V, both VMware and Citrix were already shipping VMotion and XenMotion, respectively. Had Nissan picked either of these products at the time, it could already be enjoying live migration capability. But D'Antonio said he was comfortable with Nissan's decision to settle on Microsoft Hyper-V.
"We're a Microsoft shop, and they were the first ones that we looked at …. We have a good relationship with Microsoft that we leverage and utilize," D'Antonio said.
Chris Wolf, a senior analyst at Midvale, Utah-based Burton Group, said it's not unusual for vendors to entice customers with very attractive software and support agreements in exchange for being reference customers. From the customer's perspective, "I'm sure they were able to negotiate some very good incentives relative to the price," he said.
In fact, a lot of technology decisions are made for business reasons, Wolf said. Burton Group has several very large customers running Hyper-V. "For one company, it was a decision handed down by the CIO, and they came to us saying, 'The decision has already been made. Now that we have it, tell us what pitfalls to avoid.' "
In heavily entrenched Microsoft shops, there's a also desire to stick with a familiar interface. "There's a lot to be said for product familiarity. A lot of IT shops would rather live with a product's shortcomings than use unfamiliar technology," Wolf added.
The Live Migration feature in Hyper-V R2 works as advertised, Wolf said, although it's not as quick as VMware's in moving virtual machines off a host. All things being equal, it could take up to twice as long to move all the virtual machines off a Hyper-V host as off a VMware host, he said, which could have implications for maintenance windows.
Wolf also said Burton Group will not certify Hyper-V R2 as enterprise-ready this year because it does not support virtual SMP for Linux guests. According to Burton Group, VMware and Citrix XenServer are the only two enterprise-ready hypervisor platforms on the market.