Piotr Zierhoffer

D-reserve: distributed reliable service environment

Nowadays, a major paradigm of large scale distributed processing is service-oriented computing. To improve the availability and reliability of the SOA-based systems and applications, a Reliable Service Environment ReServE, providing an external support of web services recovery, has been proposed. The functionality of ReServE can be enhanced by distributing its architecture. However, this causes several problems, which have to be solved. In this paper we address these problems and propose their solution.

ReServE service: an approach to increase reliability in service oriented systems

Heterogeneous environment of service-oriented computing turns to be very error-prone, due to the loose-coupling and a great number of independent components that are susceptible to failures. Therefore, we propose the ReServE service, which improves the reliability of the SOA-based systems and applications. The proposed service ensures that after a failure occurrence, the state of a business process is transparently recovered, and it is consistently perceived by the business process participants: clients and web services.

Applying message logging to support fault-tolerance of SOA systems

Abstract This paper addresses a problem of increasing fault-tolerance of serviceoriented systems built of RESTful web services. To solve such a problem, rollbackrecovery protocol is proposed. The protocol employs known rollback-recovery techniques, however, it modifies and specially adjusts them for specific characteristics of the SOA systems. The paper includes a proof of safety property of the proposed protocol.

The Impact of Service Semantics on the Consistent Recovery in SOA

This paper addresses a problem of consistent recovery of SOA processing. So far, the recovered state was considered as consistent if all events that have occurred before the failure were transparently recovered. However, providing such a strict consistency introduces a high performance overhead. Thus, we propose the semantic-based classification of services that enables to slack the notion of consistent recovered state from the viewpoint of services. We also present the extension of RESERVE rollback-recovery protocol that guarantees the proposed relaxed recovery consistency.

Towards Relaxed Rollback-Recovery Consistency in SOA

Nowadays, one of the major paradigms of distributed processing is SOA. To improve the reliability of SOA-based systems, a ReServE service that ensures recovery of consistent processing state, has been proposed. ReServE introduces a high overhead during failure-free computing. Thus, in this paper we propose relaxed recovery consistency models that allow optimization of rollback-recovery in SOA. We propose their formal definitions, and discuss the conditions under which these models are provided by ReServE.

Handling consistent web service recovery in a RESTful way

Over the past decade, REST has become the desired standard used for the design and development of highly scable web services. Reliability requirements of such service are more and more stringent. This paper represents our initial efforts towards the problem of increasing fault tolerance of RESTful services. We propose RESTful recovery consistency model ensuring that recovered processing state respects REST constrains. Next, we propose the recovery protocol that meet the proposed recovery consistency model requirements, and apply it in the existing ReServE service.

The impact of RESTful semantics on reducing the logging overhead in SOA

Nowadays, one of the major paradigms of distributed processing is service-oriented computing. Although SOA-based applications have many advantages, they are also highly error-prone. To improve the availability and reliability of SOA-based systems and applications, a Reliable Service Environment RESERVE, providing an external support of web services recovery has been proposed. In this paper we focus on RESTful web services, based on Representational State Transfer (REST) paradigm, and propose the enhancement of RESERVE service that allows to decrease the overhead introduced by RESERVE due to taking advantage of REST characteristics.

The External Recovery Problem

We consider an external recovery problem, where a system is divided into autonomous subsystems which can be recovered only by the means of logging the messages exchanged between the subsystems. The question follows: what restrictions to the subsystems autonomy are required to make the external recovery possible? We present example solutions affecting different aspects of systems independence.

Garbage Collection for Service Oriented Distributed Reliable Environment D-ReServE

D-ReServE increases reliability of SOA-based systems in case of failure occurrence. The fault-tolerant information in D-ReServE is stored in the Stable Storage, which available space depletes with time. Thus, in this paper we propose a garbage collection protocol for D-ReServE that allows the periodic purging of the Stable Storage, and discuss the challenges of garbage collection due to the nature of SOA systems.