Object and process migration in .NET

Most of today´s distributed computing systems in the field do not support the migration of execution entities among computing nodes during runtime. The relatively static association between units of processing and computing nodes makes it difficult to implement fault-tolerant behavior or load-balancing schemes. The concept of code migration may provide a solution to the problems mentioned above. It can be defined as the movement of process, object or component instances from one computing node to another during system runtime in a distributed environment. Within our paper we describe the integration of a migration facility with the help of aspect-oriented programming (AOP) into the .NET framework. AOP is interesting as it addresses nonfunctional system properties on the middleware level, without the need to manipulate lower system layers like the operating system itself. We have implemented two proof-of-concept applications, namely a migrating Web server as well as a migrating file version checker application. The paper contains an experimental evaluation of the performance impact of object migration in context of those two applications.