Mohamed S. Mansour

Implementing Diverse Messaging Models with Self-Managing Properties using IFLOW

Implementing self-management is hard, especially when building large scale distributed systems. Publish/subscribe middlewares, scientific visualization and collaboration tools and corporate operational information systems are examples of one class of systems, distributed information flow infrastructures, that could benefit from self management. This paper presents IFLOW, an autonomic middleware for implementing these different distributed systems in a self-managing way. IFLOW reduces different messaging models down to a common information flow abstraction, creates a self-managing implementation of that abstraction and then provides a substrate for building diverse information flow systems. We describe the design and implementation of IFLOW and describe case studies of implementing different messaging models as self-managing systems.

I-queue: smart queues for service management

Modern enterprise applications and systems are characterized by complex underlying software structures, constantly evolving feature sets, and frequent changes in the data on which they operate. The dynamic nature of these applications and systems poses substantial challenges to their use and management, suggesting the need for automated solutions. This paper considers a specific set of dynamic changes, large data updates that reflect changes in the current state of the business, where the frequency of such updates can be multiple times per day. The paper then presents techniques and their middleware implementation for automatically managing requests streams directed at server applications subjected to dynamic data updates, the goal being to improve application reliability in face of evolving feature sets and business data. These techniques (1) automatically detect input patterns that lead to performance degradation or failures and then (2) use these detections to trigger application-specific methods that control input patterns to avoid or at least, defer such undesirable phenomena. Lab experiments using actual traces from Worldspan show a 16% decrease in frequency of server restarts when using these techniques, at negligible costs in additional overheads and within delays suitable for the rates of changes experienced by this application.

Isolation points: Creating performance-robust enterprise systems

This article explores a performance isolation-based approach to creating robust distributed applications. For each application, the approach is to understand the performance dependencies that pervade it and then impose constraints on the possible ‘spread’ of such dependencies through the application. The mechanisms used for this purpose, termed isolation points, are software abstractions inserted at key program locations: (1) in application interfaces, (2) in middleware implementations for making remote requests, and (3) in the system interfaces used by middleware and applications. This article demonstrates the utility of isolation points by using them to implement higher level abstractions that improve the performance-robustness of representative enterprise applications. The I-Queue abstraction uses isolation points to implement performance-robust messaging, targeting the message queues used in distributed enterprise codes. By appropriately orchestrating message dispatching, I-Queue can achieve an improvement of 16--32% in dispatched message locality based on traces obtained from the large-scale e-Pricing® search engine operated by Worldspan L.P.