Leveraging virtualization to optimize high-availability system configurations

Leveraging redundant resources is a common means of addressing availability requirements, but it often implies redundant costs as well. At the same time, virtualization technologies are bursting into data centers with the promise of reducing costs through resource consolidation. Can virtualization and High Availability (HA) technologies be combined to optimize availability while minimizing costs? Yes, but merging them properly introduces new challenges. Drawing on practical experiences from an IBM development test lab, this paper looks at how virtualization technologies, methodologies, and techniques can augment and amplify traditional HA approaches while avoiding potential pitfalls. Special attention is paid to resource sharing, applying conceptual models (such as Active/Active and Active/Passive) to virtualized environments, stretching virtual environments across physical machine boundaries, and avoiding hazards that await the unwary.