Availability "Weak Point Analysis over an SOA Deployment Framework Lei Xiel,Jing Luo2,Jie Qiu2,John A Pershing3,Ying Li2,Ying Chen2 1Department of Computer Science,Nanjing University xielei@dislab.nju.edu.cn 2 IBM China Research Lab {jingluo,qiujie,lying,yingch}@cn.ibm.com 3 IBM T.J.Watson Research Center,Ha wthorne,NY 10532 pershng@us.ibm.com I Abstract-Availability is one of the important factors to to the workflow specification,the availability for the chains be considered for business-driven IT service management.This of resources over the IT infrastructure forms the end to end paper addresses the issue of analyzing what we call availability availability. weak-points in an SOA deployment framework,leveraging work- flow definitions to specify the high availability requirement at the Note that,even if all single points of failure have been business process level.In our weak-point analysis framework,we made redundant,some of these (redundant)resources still present an effective analysis methodology to calculate the optimal may not exhibit the necessary availability level to satisfy high availability solution with minimum cost,while meeting the the requirements of the business processes.We refer to this business level availability requirements.We evaluate the weak- point analysis methodology,and show that our methodology can situation as an availability weak-point,and it may be necessary identify a near-optimal solution for availability enhancement over to introduce even more redundancy in order to meet the the SOA deployment framework. availability requirements. The key to deliver successful,robust solutions is determin- I.INTRODUCTION ing the right level of high availability IT infrastructure [5]:not Service-Oriented Architecture (SOA)has opened up new enough could result in costly outages,and too much could be opportunities for organizations seeking more flexibility and an expensive waste.So it makes sense to perform availability responsiveness to business demands over the large scale de- analysis over the distributed IT infrastructure in conjunction ployed IT infrastructures.Availability of computing resources with business level requirements,and further plan for high is an important consideration for IT service management. availability solutions. Note,though,that the actual availability requirements are Therefore,detecting and analyzing the availability weak dictated by the various business processes and services that are points from the SOA deployment topology is the premise for supported by the IT infrastructure;the availability requirement applying high availability (HA)solutions [1][2][3]over the of an individual resource is simply to support the overall IT infrastructure.In this paper we propose a workflow-based availability of the busines processes and services.Business weak-point analysis methodology over the SOA deployment services today are not only doing more work but also have framework:the novelty of our approach is that we propose more users,often spread out across the globe,and requiring a framework to analyze the weak-points and give indications near 24/7 availability. for optimal HA solutions over the deployment topology.Using The basic principle of high availability management for our framework,it can be determined which components from IT infrastructure is to eliminate single points of failure by the topology need to be HA enhanced,and to what level providing redundancy,which can be implemented to varying they should be enhanced to satisfy the business-level HA degrees with a wide range of associated cost and perfor- requirements,while keeping the overall cost close to the mance considerations.Common high availability techniques minimum. include clustering [1],hot failover mechanisms [2][3],recur- The rest of the paper is organized as follows:In section sive restartability [4],redundant arrays of independent disks II we describe the basic structure of our availability weak- (RAIDs),and other approaches.From the business process point analysis framework.We introduce the workflow based level for enterprise applications,the availability metric is methodology for calculating a near-optimal solution in section actually an end to end availability;thus,the business process III.Section IV shows the experiment evaluation to depict can be depicted as a workflow.For general applications the the efficiency of our analysis framework.In Section V we workflow crosses the typical three-tiered IT infrastructure: introduce the related works.Section VI concludes the paper. web tier,middleware tier,database tier.Therefore,according II.THE WEAK-POINT ANALYSIS FRAMEWORK IThis paper work is done when the first author is working as an intern in The overall weak-point analysis framework is shown in IBM China Research Lab. Fig.1.The framework includes the following three majorAvailability “Weak Point” Analysis over an SOA Deployment Framework Lei Xie1 , Jing Luo2 , Jie Qiu2 , John A Pershing3 , Ying Li2 ,Ying Chen2 1 Department of Computer Science, Nanjing University xielei@dislab.nju.edu.cn 2 IBM China Research Lab {jingluo, qiujie,lying, yingch}@cn.ibm.com 3 IBM T. J. Watson Research Center, Ha wthorne, NY 10532 pershng@us.ibm.com 1 Abstract— Availability is one of the important factors to be considered for business-driven IT service management. This paper addresses the issue of analyzing what we call availability weak-points in an SOA deployment framework, leveraging work- flow definitions to specify the high availability requirement at the business process level. In our weak-point analysis framework, we present an effective analysis methodology to calculate the optimal high availability solution with minimum cost, while meeting the business level availability requirements. We evaluate the weak￾point analysis methodology, and show that our methodology can identify a near-optimal solution for availability enhancement over the SOA deployment framework. I. INTRODUCTION Service-Oriented Architecture (SOA) has opened up new opportunities for organizations seeking more flexibility and responsiveness to business demands over the large scale de￾ployed IT infrastructures. Availability of computing resources is an important consideration for IT service management. Note, though, that the actual availability requirements are dictated by the various business processes and services that are supported by the IT infrastructure; the availability requirement of an individual resource is simply to support the overall availability of the busines processes and services. Business services today are not only doing more work but also have more users, often spread out across the globe, and requiring near 24/7 availability. The basic principle of high availability management for IT infrastructure is to eliminate single points of failure by providing redundancy, which can be implemented to varying degrees with a wide range of associated cost and perfor￾mance considerations. Common high availability techniques include clustering [1], hot failover mechanisms [2] [3], recur￾sive restartability [4], redundant arrays of independent disks (RAIDs), and other approaches. From the business process level for enterprise applications, the availability metric is actually an end to end availability; thus, the business process can be depicted as a workflow. For general applications the workflow crosses the typical three-tiered IT infrastructure: web tier, middleware tier, database tier. Therefore, according 1This paper work is done when the first author is working as an intern in IBM China Research Lab. to the workflow specification, the availability for the chains of resources over the IT infrastructure forms the end to end availability. Note that, even if all single points of failure have been made redundant, some of these (redundant) resources still may not exhibit the necessary availability level to satisfy the requirements of the business processes. We refer to this situation as an availability weak-point, and it may be necessary to introduce even more redundancy in order to meet the availability requirements. The key to deliver successful, robust solutions is determin￾ing the right level of high availability IT infrastructure [5]: not enough could result in costly outages, and too much could be an expensive waste. So it makes sense to perform availability analysis over the distributed IT infrastructure in conjunction with business level requirements, and further plan for high availability solutions. Therefore, detecting and analyzing the availability weak points from the SOA deployment topology is the premise for applying high availability (HA) solutions [1] [2] [3] over the IT infrastructure. In this paper we propose a workflow-based weak-point analysis methodology over the SOA deployment framework: the novelty of our approach is that we propose a framework to analyze the weak-points and give indications for optimal HA solutions over the deployment topology. Using our framework, it can be determined which components from the topology need to be HA enhanced, and to what level they should be enhanced to satisfy the business-level HA requirements, while keeping the overall cost close to the minimum. The rest of the paper is organized as follows: In section II we describe the basic structure of our availability weak￾point analysis framework. We introduce the workflow based methodology for calculating a near-optimal solution in section III. Section IV shows the experiment evaluation to depict the efficiency of our analysis framework. In Section V we introduce the related works. Section VI concludes the paper. II. THE WEAK-POINT ANALYSIS FRAMEWORK The overall weak-point analysis framework is shown in Fig.1. The framework includes the following three major