Virtualization Technology News and Information
Real World Virtualization: Realizing the Business Benefits of Server Virtualization

Eric Spiegel, CEO of XTS, continues his discussion of real world virtualization, this time focusing on Server Virtualization.  He talks with Dave McCrory, co-author of the book Advanced Server Virtualization: VMware and Microsoft Platforms in the Virtual Data Center.

Server Virtualization
For insights into challenges in the server virtualization world, I spoke with Dave McCrory, an independent virtualization consultant and co-author of “Advanced Server Virtualization.”

According to McCrory, management of virtual server environments can be extremely daunting. “There is no comprehensive single management tool for planning and troubleshooting because most tools have no or very little awareness of virtual machines,” says McCrory. “This is because they weren’t originally built with virtualization in mind, but instead are being adapted for virtualization management. To make things more challenging, virtualization technologies are still evolving into next generation hypervisor environments, which, instead of residing on top of Linux or Microsoft Windows, have their own operating system on bare metal hardware.” There are some best practices that can help you get a handle on this fast growing and changing technology. McCrory provided these four best practices that will allow you to avoid common pitfalls.

1. Standard conventions. Standardize on a method to track machines and what resides on them to better organize your virtual assets. “The more you can standardize, the easier it is to look at one physical host and know exactly what is installed there,” says McCrory. “This will help you better manage your virtual assets and avoid shutting down a server and unintentionally impacting more users or applications than you expected.”

2. Test thoroughly. Seems like common sense, but it makes it no less important. McCrory suggests starting a pilot with IT because they will be the most tolerant subjects. “A pilot gives the IT group a chance to encounter issues the eventual end-users will also come across,” says McCrory. “And it gives your administrators the chance to practice and get comfortable with this technology, while serving a friendly audience.” McCrory goes on to say, “When you do roll out production applications, I strongly recommend not starting with more complex applications that stretch limits of virtualization. A bad choice would be an Oracle database with 250 gigs of storage with millions of daily transactions. Instead, stick to something with a smaller number of users and a lighter weight application.”

3. Track performance. Find an information gathering solution to track what machines are doing what, grouped by virtual machines and their physical hosts. If you have the budget and skills, you can build something custom, or just start with the vendors’ monitoring solutions, such as VMware’s Virtual Center. “It is valuable to understand your virtual and physical machine utilization trends,” says McCrory. “If utilization on physical machine is only at 30 percent, you can add more virtual machines without incurring the extra expense of adding new equipment.”

4. Leverage savings opportunities. There are cost savings opportunities to be had here as well. McCrory suggests leveraging your virtual machine savings potential in support of your SLAs. “You can get more savings in high availability because one physical server with four virtual machines can serve as a fail-over for five physical machines, saving you hardware costs.” Also, consider how a virtual machine’s transient nature could result in a software license being consumed, at which point it’s decommissioned. “It is not easy to manage the “virtual” consumption of licenses, so it is best to thoroughly review your license agreements to see if you are bound by physical CPUs,” says McCrory. “There may be hidden benefits, but if you aren’t sure, it is best to have a discussion with the vendor.”

McCrory has seen many of his clients try to virtualize everything early on, only to find some applications and machines are not good candidates for virtualization. Some make the mistake of continuing to struggle and try to make them work, only to compound the problem. “It is best to benchmark what machines are currently consuming so you can decide which physical servers are good candidates to host virtual machines,” says McCrory. “Finally, keep in mind that a hypervisor virtual server runs with about .5 percent overhead compared to the 12 percent overhead in a non-hypervisor environment.”

To sum up, application and server virtualization offer challenges as well as a myriad of benefits. If you follow standards, thoroughly test through a pilot program (making sure to identify appropriate test subjects), and continuously analyze your virtual environments, you will surely experience fewer “virtual headaches”… and actualize the real benefits that virtualization offers.

Quoting from the original article, here.


Published Wednesday, June 14, 2006 6:12 PM by David Marshall
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