A Decentralized Redeployment Algorithm for Improving the Availability of Distributed Systems

摘要

In distributed and mobile environments, the connections among the hosts on which a software system is running are often unstable. As a result of connectivity losses, the overall availability of the system decreases. The distribution of software components onto hardware nodes (i.e., the system's deployment architecture) may be ill-suited for the given target hardware environment and may need to be altered to improve the software system's availability. Determining a software system's deployment that will maximize its availability is an exponentially complex problem. Although several polynomial-time approximative techniques have been developed recently, these techniques rely on the assumption that the system's deployment architecture and its properties are accessible from a central location. For these reasons, the existing techniques are not applicable to an emerging class of decentralized systems marked by the limited system wide knowledge and lack of centralized control. In this paper we present an approximative solution for the redeployment problem that is suitable for decentralized systems and assess its performance.