Virtualization is quickly gaining traction in IT departments around the world. According to Symantec's recent Virtualization and Evolution to the Cloud survey, 76 percent of enterprises are at least discussing virtualization. In the wake of the recent recession, the benefits are too valuable for businesses to ignore. Virtualization can reduce capital/operational expenditures, allow for faster deployment of computing resources, and facilitate management of business processes. Applicable to more than just servers, virtualization is becoming more common in a variety of different IT applications, including storage and desktops. Despite the inroads the technology has made in the data center, however, organizations have remained reluctant to virtualize business-critical applications.

According to the virtualization survey, among organizations implementing server virtualization, more than 50 percent plan to implement virtualization for Web and database applications over the next 12 months. When it comes to business-critical applications, however, 40 percent of CEOs and 42 percent of CFOs are reluctant to make the leap. The most common concern keeping enterprises from making the transition is reliability, cited by 78 percent of survey respondents.

Virtualization Challenges
A successful shift to a virtualized data center requires meeting goals of cost-savings and high availability. Tight budgets mean reduced staff and limited resources are the norm in IT departments today; and cost savings can only be realized if application uptime remains as high as possible. For the typical enterprise, the recovery time objective (RTO [the tolerable amount of application downtime for business-critical applications]) is less than one hour. In some cases, no more than a few minutes can be tolerated because downtime can mean millions of dollars in lost revenue or worker productivity. In light of these needs, IT staff should be aware of the following challenges inherent to a virtualized environment.

Consolidated Points of Failure
Virtualization can increase availability risks by consolidating the points of failure on fewer servers. In addition, further complexities are introduced by ensuring high availability for business-critical applications such as Exchange Server, SQL, SAP, and Oracle that are deployed on a combination of physical and virtual server nodes. For example, an ERP application may have middleware components running in a virtual server, but the underlying database is on a physical server. This combination of increased complexity and "putting all your eggs in one basket" can lead to single points of failure that could disrupt business operations if it is not addressed.

Visibility Limitations
One additional risk posed by virtualization is the lack of visibility into virtualized apps for troubleshooting purposes. When the application components such as the OS and drivers are encapsulated to make portability easier, the result is reduced visibility into the state of those components.

Human Error
Because multiple tools from varying vendors will increase management complexity, human error is more likely to occur with virtualized software. This increases because many high-availability tools are unable to monitor application health sufficiently. According to the Uptime Institute, a New York-based research and consulting organization that focuses on data-center performance, human error causes roughly 70 percent of the problems that plague data centers.

Take a Proactive Approach
In order to mitigate these risks and ensure high application availability, IT staff needs to carefully consider their organization's approach to virtualization. By taking a proactive approach to application management, rather than simply reacting to problems as they occur, you will significantly improve your uptime by avoiding problems before they occur.

Finding the right management software is the simplest way to ensure high availability, but most solutions from virtualization vendors fail to fully meet the scope of an organization's needs. As you consider implementing a comprehensive high-availability solution, look for the following characteristics.

Extensive Support
Look for a solution that provides support for not just the hardware, but also for the different operating systems you run, including UNIX, Windows, Linux, and virtual platforms, as well as a wide range of heterogeneous hardware configurations. Implementing one solution across all platforms will reduce complexity and increase reliability, with the additional benefit of minimizing costs related to training and administration.

Automated Failover
An effective solution will detect faults in an application and all its dependent components, including the associated database, operating system, network, and storage resources. In the event of an outage, the solution must be able to restart the application, connect it to the appropriate resources, and resume normal operations.

Automated Disaster Recovery Testing
With servers and applications constantly changing, the regular testing of a disaster recovery strategy is critical in order to guarantee a successful recovery in the event of a system or site-wide outage. Non-disruptive testing is necessary in order to maintain productivity while identifying potential issues.

Multi-cluster Management and Reporting
Visibility is one of the most important goals in virtualization, but it remains difficult to achieve. Administrators need to be able to monitor, manage, and report on multiple clusters on different platforms, ideally from a single location. The proper reporting tools also make it easier to resolve problems and streamline the operations of your virtualized systems.

Conclusion
The risk of downtime to business-critical applications keeps many enterprises from realizing the full benefits of virtualization. While there are increased risks due to the consolidation of resources and lack of visibility, these can be managed by implementing a virtualization solution with robust features. By automating as much of the process as possible, and improving visibility into virtualized applications, businesses can avoid the pitfalls and enjoy increased productivity and efficiency in the data center.