7 tips for succeeding with virtualization
- — 21 October, 2008 10:35
"While some environments could support virtual-only clusters for testing, the more common scenario would have, for instance, two virtual elements and one physical one supporting a single IT service," says Cameron Haight, a Gartner research vice president. "IT still needs to correlate performance metrics and understand the profile of the service that spans the virtual and physical infrastructures. Sometimes people are lulled into a false sense of security thinking the tools will tell them what they need to know or just do [the correlation] for them."
IT managers should push their vendors for reporting tools that not only show what's happening in the virtual realm but also display the physical implications -- and potentially the cause -- of an event. Detailed views of both environments must be married to correlate why events take place in both realms.
For instance, if utilization on a host server drops from 20 percent to 10 percent, it would be helpful to know the change came about because VMware Distributed Resource Scheduler (DRS) moved virtual machines to a new physical server, Haight says. In addition, knowing when and where virtual machines migrate can help prevent a condition dubbed "VMotion sickness" from cropping up in virtual environments. This occurs when virtual move repeatedly across servers -- and bring problems they might have from one server to the next, Haight says. Proper reporting tools, for example, could help an administrator understand that a performance problem is traveling with a virtual machine unbeknown to DRS.
5. Eliminate virtual blind spots
The fluid environment created by virtualization often includes blind spots. "We monitor all physical traffic, and there is no reason why we wouldn't want to do the same for the virtual traffic. It's a huge risk not knowing what is going on, especially when the number of virtual servers is double what you have for physical boxes," says Nick Portolese, senior manager of data center operations at Nielsen Mobile.
Portolese supports an environment with about 30 VMware ESX servers and 500 to 550 virtual machines. Early on, he realized he wasn't comfortable with the amount of network traffic he could monitor in his virtual environment. Monitoring physical network traffic is a must, but he found the visibility into traffic within the virtual environment was non-existent.
Start-up Altor Networks provided Portolese with what he considered necessary tools to track traffic in the entire environment. Altor's Virtual Network Security Analyzer (VNSA) views traffic at the virtual -- not just the network -- switch layer. That means inter-virtual-machine communications or even virtual desktop chatter won't be lost in transmission, the company says. VNSA provides a comprehensive look at the virtual network and analyzes traffic to give network security managers a picture of the top application talkers, most-used protocols and aspects of virtualization relevant to security. It's a must-have for any virtual environment, Portolese says.