ÿþ<html > <link href="data/symbole1.jpg" rel="shortcut icon" type="data/ico"> <head> <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> <link rel="stylesheet" type="text/css" href="css1.css" /> <title>LBACT Tool</title> </head> <body> <table width="100%" border="0" cellspacing="0" cellpadding="0"> <tr> <td width="15%" rowspan="4" >&nbsp;</td> <td colspan="2" class="header">&nbsp; <div style="margin-left:40px;"> </div></td> <td width="15%" rowspan="4" >&nbsp;</td> </tr> <tr> <!-- <td colspan="2" class="menu"> <ul> <li><a href="actualité.html"/>Actualit&eacute;</a></li> <li><img src="data/symbole1.jpg" />&nbsp;</li> <li><a href="agence de voyage.html"/>Agence de voyage </a></li> <li><img src="data/symbole1.jpg" />&nbsp;</li> <li><a href="top 10.html"/>Top 10</a></li> <li><img src="data/symbole1.jpg" />&nbsp;</li> <li><a href="inscription.html"/>Inscription </a></li> </ul> </td> --> </tr> <tr> <td width="18%" class="box"> <h3>BPEL Clustering Architecture</h3> <ul> <li><i><a href="overview1.html"/>Overview</a></i></li> <li><i><a href="impl.html"/>Implementation</a></i></li> </ul> <h3>LBACT Tool</h3> <ul> <li><i><a href="overview2.html"/>Overview</a></i></li> <li><i><a href="spec.html"/>Test specifications</a></i></li> </ul> <h3>Conformance Test platform</h3> <ul> <li><i><a href="overview3.html"/>Overview</a></i></li> <li><i><a href="observer.html"/>Observer</a></i></li> <li><i><a href="tester.html"/>Tester</a></i></li> </ul> <h3>How to use LBACT?</h3> <ul> <li><i><a href="gui.html"/>LBACT GUIs</a></i></li> <li><i><a href="casestudy.html"/>Case study</a></i></li> </ul> <h3>Contact</h3> Afef Jmal Maâlej <br/> ReDCAD - DGIMA - ENIS <br/> Route de la Soukra km 3.5<br/> B.P. 1173, 3038, Sfax - Tunisia<br/> <b>Email:</b> <a href="mailto:afef.jmal@redcad.org">afef.jmal@redcad.org</a> <h3>Contributors</h3> <a href="http://www.redcad.org/members/afef.jmal" target="_blank"><font color="black">MSc. Afef Jmal Maâlej</font></a><br> <a href="http://www.redcad.org/members/zeineb.benmakhlouf" target="_blank"><font color="black">Ing. Zeineb Ben Makhlouf</font></a><br> <a href="http://www.redcad.org/members/mkrichen/" target="_blank"><font color="black">Dr. Moez Krichen</font></a> <br> <a href="http://www.redcad.org/members/jmaiel" target="_blank"><font color="black">Prof. Mohamed Jmaiel</font></a> <td> <br> <a name="haut"> <h3><center><font color="dark orange"><i>BPEL Clustering Architecture Overview</i></font></center></h3></a> <p align="justify"> The following components are sufficient to guarantee a BPEL clustering architecture:<br> - Multiple BPEL servers on different nodes.<br> - Load Balancer in charge to distribute client requests to BPEL servers.<br> - A dehydration store database shared by all the BPEL servers.<br> As a load balancer is available, BPEL processes are shared between BPEL servers in the cluster. If a BPEL server becomes faulty, the remaining BPEL servers in the cluster continue to treat the unfinished process of this server from the last point of dehydration. The next figure provides an overview of BPEL clustering environment in general (considering n BPEL servers). <center><img src="data/arch.PNG"/></center> <center><em>General BPEL Clustering Architecture</em></center> <ol type="1"> <li><b>Choice of the BPEL Server:</b><br> <p align="justify"> Oracle BPEL Process Manager provides a solution for designing, deploying and managing BPEL processes. In particular, the BPEL Console allows testing deployed processes through an automatically generated HTML form interface or by passing specific XML message content to it. This test page includes stress test capability that makes it possible to do load testing of deployed BPEL processes on a BPEL server, and then to view the performance statistics of the flow under stress. That is why we opted for BPEL server choice in our work. Moreover, it is free and multi-platform. Also, it supports being ordered by a load balancer. <li><b>Choice of the Load Balancer:</b><br> <p align="justify"> Oracle Http Server (OHS) is based on the Apache Web Server. OHS extends Apache with several personalized modules to provide specialized features of Oracle in addition to a highly available infrastructure that can manage processes and failover mechanism.<br> The most important module is mod oc4j. It is responsible of load balancing. This module supports three distinct types of routing: (a) random, (b) round-robin, and (c) metric-based. Random and round-robin algorithms support the fact of assigning a weight to a node. In that case, mod oc4j module distributes the requests according to the routing weight configured for each host. In the following, we describe the previously enumerated supported routing types by the mod oc4j module:<br> (a) Random: In random load balancing, requests are routed to servers at random. This algorithm is recommended only for homogeneous cluster deployments, where each server runs on a similarly configured machine. The possibility that the load cannot be equally balanced on a small number of requests remains a disadvantage of the random load balancing.<br> (b) Round-robin: When a load balancer is configured to use this method, it rotates incoming requests around the servers it manages. This method has the advantages to be simple, cheap and very predictable. The main drawback is that it does not consider the availability of servers.<br> (c) Metric-based: Metric-based is a way to distribute the load between servers based on the status of the metric that reports each server. The possibility that the load can be equilibrated remains an opportunity for metric-based load balancing. <li><b>Choice of the Database:</b><br> <p align="justify"> In case of a BPEL server failure, the next available BPEL server resumed the current process from the last point of dehydration. All BPEL servers share the same database.<br> Oracle Database Express Edition and Microsoft SQL Server represent the databases that support the BPEL server. Oracle Database Express Edition is the data base adopted in our work. This tool allows, via a graphical interface, managing database objects, viewing sessions and doing SQL. It is multi-platform and free. </ol> </p> <center><a href="#haut"><IMG SRC="data/Haut.jpg" align="center"></a>&nbsp;&nbsp;&nbsp;<a href="#haut"><font color="#9BDB18"><big>Top of Page</big></font></a></center> </td> </tr> <tr> <td colspan="2" class="footer"> <p align="center" style="text-align: center;"><font color=white><span lang="EN-US" style="">© Afef Jmal Maâlej - ReDCAD - Last Updated: December 2012.<o:p/></span></font></p> </div> </td> </tr> </table> </body> </html>