Practical Approaches to Cloud-based High Availability
Although high availability (HA) is a complex activity, regardless of the application, clouds and their virtualization platforms actually make this objective simpler and more straightforward. Virtualization as an abstraction from the physical platform creates a new opportunity for HA. This article explores some of the practical approaches to cloud-based high availability, including stateless failover and the more useful stateful failover.
You will also discover the various open source software components at play in HA systems. The goal in designs such as this built around redundancy is the elimination (to an extent) of the single point of failure. This article explores the concepts of redundancy and failover as applied to virtualization environments in addition to the open source offerings for software HA. The approaches discussed in this article are capable of operating with commodity hardware. This still implies the failure levels consistent with commodity hardware, but the approaches do improve on it. True enterprise-level fault tolerance, as evident in IBM mainframes, is a complex and detailed science covered by a combination of hardware and software. This article explores only those techniques implemented in pure software.