LinuxWorld Virtualization is certainly creating a lot of buzz in the industry, but despite the technology's hefty promises of cost cutting and consolidation, the vast majority of businesses are still running on physical hardware.
Tony Iams, senior analyst of enterprise IT research firm Ideas International has been busy sniffing around the data centers to get a feel for how the emerging technology is changing the way IT works. Ideas interviewed around 50 companies of various sizes that have deployed virtualization. The firm focused both on businesses using the industry-standard x86 platform as well as other classes of systems such as Unix, IBM's System i and mainframes.
At a LinuxWorld panel in San Francisco today, Iams explained the motivations for companies to move to a virtual platform and the pitfalls that arise from making the switch.
The dangling carrot
Ideas found the push towards virtualization is largely a bottom-up affair. The people in the IT department most often want to implement the technology to make their lives easier rather than a CFO demanding virtualization to save money.
How virtualization is actually implemented is generally split between x86 and UNIX servers. According to Iams, x86 virtualization is typically driven by large-scale consolidation - where a business has several fixed workload servers and want to stack them on virtual machines to have fewer boxes to maintain.
Unix virtualization, on the other hand, is driven by workload management and utilization. Where previously the IT staff would buy a large server configured for the peak workload of an application, virtualization allows the resources to be dynamically changed based on demand without shutting it down.
Few businesses interviewed were deploying storage virtualization. Most found, after crunching the numbers, that it wasn't worth the effort, and opted to buy more, traditional, storage devices.
For x86 platforms, the break-even point of consolidation is five-six servers. If a business is moving less than that onto a machine, they're spending more on virtualization software than they are saving on reducing infrastructure.
For Unix systems with variable workloads, being able to configure an application for average usage rather than peak times saves money if three or more can be put into a box running a virtual environment.
The jury is still out on the impact of virtualization upon operating costs. There's the intuitive benefit of reducing time of server deployment, but this is a bit tricky to quantify. Sure, creating a virtual server avoids having to spec out the system, buy the hardware, wait for it to be shipped, install, bring it up, etc. - and that's valuable from a manager's standpoint. But you aren't saving money per se.
Ideas International found that many users were performing internal total cost of operation studies, but none are yet complete. Some are doing the the research, but nobody was willing to give out metrics just yet.
Businesses were drawn to VMWare primarily for VMotion. Customers either routinely used VMotion for production workloads, or had a strong interest in using it in the future.
Iams said he was surprised by how often Ideas ran across businesses running Microsoft Virtual Server, and also how many were pleased with it. The research firm found that while often businesses were turned off by the heavyweight Windows OS host and lack of manageability, they also found the software matched the maturity of the organization. Many weren't yet ready to use the advanced features of more robust virtual software such as VMWare, but expect Microsoft to fill in the holes later - which is when the business would take the plunge as well. Iams noted the faith of many respondents in the interoperability of virtualization software. The consensus was that if Microsoft doesn't eventually deliver, they will be able to switch between virtual disk files.
Ideas found customers were generally hesitant about implementing XenSource. Overall, there were concerns about the requirements for customized kernel and lack of commercial support. The stigma of open source is still a hurtle for Xen to overcome as well. Companies remain reluctant to implement software when they don't see a company behind to hold accountable.
On the x86 platform, Ideas found that virtualization made it much easier to deploy new systems. But this comes at a cost. The ease of creating virtual servers increases the demand for them. Suddenly, there are more servers to manage than ever before. From a manageability standpoint, going virtual is not all that different than physical, but the burden can actually become worse.
Ideas found less complaints on the Unix side. Managers typically treat virtual servers the same as physical servers and continue to use the same tools.
Iams parted with recommendations for company's considering consolidation.
- Know your apps. Be sure to classify the suitability of workloads for virtualization by measuring performance characteristics over time and understanding their dependency on different resources (CPU, memory, I/O.)
- Choose the appropriate virtualization platform. I/O-heavy applications will take a hit on x86 platforms, so for critical workloads, you should consider Unix or mainframes for today.
- Evaluate different virtualization approaches and products. Don't set your heart on one product before checking out VMWare, MS Virtual Server, Xen, SWsoft, Viruozzo, etc.
- Adapt management procedures and tools for virtualization. Focus on managing the relationship and dependencies between virtual resources and their physical counterparts. Large levels of consolidation need much better tools to manage virtual servers.
- Maintain modularity between tools for managing physical server resources, virtual server resources, and storage resources. Don't get bogged down into having one over-arching framework controlling everything passing information between levels. ®