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Server virtualization is beginning to be deployed in healthcare information technology (IT), and holds great potential for containing IT costs and addressing application lifecycle management issues. Along with these substantial advantages come challenges and risks. This paper provides an introduction to server virtualization for hospitals and healthcare delivery organizations. It also offers best practices you can use to benefit from virtualization, while avoiding missteps that could affect the availability and performance of mission-critical healthcare IT.
IT Growth and Server Virtualization
In the U.S., larger hospitals and healthcare delivery organizations are leading the way to dramatically increased use of IT, for reasons that include improving the quality of care and patient safety.1 Cost continues to be a hurdle to IT deployment, however, including for high-priority clinical applications such as electronic medical records and computerized practitioner order entry (CPOE).
Server virtualization is getting attention as hospitals and other healthcare delivery organizations increase IT usage while seeking ways to accommodate its cost. Among many other advantages, virtualization allows healthcare delivery organizations to save money by consolidating a number of applications on the same physical server.
Server virtualization can be defined as the practice of using a software layer to let one physical computing server run multiple virtual machines that support multiple applications. A time-honored approach in the mainframe world, virtualization today involves Windows® and Linux® computer servers.
Healthcare is Mission-Critical
The surge of server virtualization now underway in business enterprises began with applications deemed less critical, characterized by lower processing requirements and tolerant of limited service outages. Advanced clinical applications can gain advantages from server virtualization that go beyond those seen in typical enterprise software applications _ although special concerns apply as well.
Virtualization that supports patient care applications puts the technology into the mission-critical realm. Here, service interruptions are unacceptable. A server/application outage of only a few minutes can be devastating when a clinician requires immediate access to the electronic health record (EHR) of a critically ill patient, for example.
While consolidating applications on fewer computer servers has significant benefits, risks exist when the underlying platform (including hardware, virtualization software layer and drivers) is not sufficiently robust. A problem that affects the platform could cause downtime or performance issues for all the applications on that platform. The incident could then be followed by a long recovery time.
Using server clustering to provide a robust platform presents another challenge. Running a single application clustered on multiple servers in a non-virtualized environment is difficult enough. With virtualization, IT personnel have to deal with the complexity of configuring, testing and maintaining multiple applications that are clustered on the same platform.
Therefore, evaluating and addressing an application’s availability requirements is important when considering a move to a virtual environment. Before exploring these and other concerns in more depth, let’s first review the basic concepts of server virtualization.
Server Virtualization Basics
In a virtualized environment, each virtual machine on a physical server exists within its own container or partition. While implementations differ, generally speaking each partition contains an application (or applications) and an instance of an operating system known as a guest operating system (OS).
A number of these partitions sit on a software layer called a hypervisor. The hypervisor is the thin, low-overhead layer that manages the basic services necessary to host the applications and their guest operating systems.
The virtual machines on a server may use the same flavor of operating system, use different releases of the OS or use entirely different types (e.g., Windows and Linux) of operating systems.
Some approaches use a host operating system below the hypervisor, but these impose system overhead. More recent solutions promote “bare metal” performance, which becomes possible when the hypervisor is implemented directly on the server hardware.
The market offers a number of commercially available software-based server virtualization products. The trend is to support virtualization that includes both Windows and Linux operating systems. VMware holds the largest market share. XenSource has introduced the concept of open-source virtualization. Microsoft likewise provides solutions for the Windows OS, and is working to extend support to the Linux OS. In addition, these vendors have announced initiatives that would allow their virtualization solutions to work together, which holds promise for standardization.
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