On the other hand, organizations that already have their applications virtualized in a server virtualization environment may be able to move them to a public cloud without any extra work. Also, the operating systems supported by server virtualization and clouds play a role in where applications can be run. For example, clouds based on Microsoft's Azure support only Windows applications.
How to decide
Choosing where to run applications depends on a number of factors:
- Characteristics and processing requirements of the applications, including performance requirements, storage requirements, security requirements, availability requirements, amount of data to transfer and service-level agreements.
- The mission-critical nature of the applications.
- The resource capacity available in the data center.
- Desired cost savings.
"You need to create a process for determining where applications should be run," says Chris Swan, chief technology officer at Capital SCF, a London-based consultancy for technology firms. This process begins with application assessment and packages such as Novell's PlateSpin Recon and VMware's Capacity Planner, which can be used to profile physical IT environments and determine which applications to virtualize for optimal performance.
Next, the processing requirements of each application (or application class) should be compared with the security concerns of running that application in each execution environment.
Once you're sure of which applications you want to move where, P2V (physical-to-virtual), V2V (virtual-to-virtual) and Z2V (zero-to-virtual) tools can help physically migrate applications among stand-alone servers, virtualized servers and clouds.
Security plays a huge role