HA-OSCAR: the Birth of Highly Available OSCAR

As clusters reach thousands of nodes, eliminating single points of failure becomes critical. The Open Cluster Group's HA-OSCAR is a solution.
Support for Asynchronous Process Execution

Telecom applications must be built to face extreme or unplanned conditions of execution. Even in typical real-life situations, subscribers are putting a lot of pressure on carriers because of their high expectations regarding system performance and availability. Customers do not expect these applications to fail or their phone requests to be delayed beyond a typical threshold. This is increasingly true as telecom applications are providing additional services, some requiring real-time characteristics.

Carrier-grade applications must be designed with these subscribers' constraints in mind, taking into account the cost of software maintenance and upgrades, service availability and scalability. Complex distributed software demands a specific programming paradigm. It has been proven over the years that complex system interfaces tend to increase the time to debug and the probability of application failure.

AEM (asynchronous event mechanism) provides an event-driven methodology of development in order to provide robust applications with a mechanism that allows reacting quickly to system events by means of user-space callbacks. In the AEM implementation, the kernel plays a major role in handling events and increases the reliability of applications. For this reason, AEM provides a flexible solution for application designers, supplying an extensible framework that allows new functionalities to be added at runtime, without rebooting the system or restarting applications. In order to reach carrier-grade requirements, HA-OSCAR plans to supply efficient support for asynchronous events.

Ibrahim Haddad (Ibrahim.Haddad@Ericsson.com) is a researcher at the Open System Lab, Ericsson Research Corporate Unit. He is coauthor, along with Richard Peterson, of the Red Hat Linux Pocket Administrator from McGraw-Hill, to be published in September 2003.

Chokchai Leangsuksun (box@latech.edu) is an associate professor of computer science at the Center for Entrepreneurship and Information Technology (CEnIT) at Louisiana Tech University. Prior to his academic career, he spent seven years in R&D with Lucent Technologies in system reliability and high-availability computing and telecommunication systems.

Stephen L. Scott (scottsl@ornl.gov) is a senior research scientist in the Computer Science and Mathematics Division of Oak Ridge National Laboratory, US. He is a founding member of OCG and presently is version 2 release manager. Previously he was the working group chair of the OSCAR Project.