On the construction of a workload generator for blogging systems

Web 2.0 technologies have enabled the collaboration and sharing of web users through emerging applications such as Wikis, Blogs and Mashups. These applications induce workloads in the web with new features, whose study is important for the development of workload generators that support capacity planning and traffic engineering activities. GBLOT is an analytical generator of workloads that can be used to evaluate the short-term behavior of blog hosting sites. The user session model of GBLOT is based on CBMGs (Customer Behavior Model Graphs). The tool provides a distributed architecture which refers to the possibility of generating requests among several computational nodes. GBLOT has been developed in three stages, each one with its own objectives and challenges. The aim of this paper is to use the experience obtained with GBLOT to show some problems in the construction of analytic workload generators for blogging systems. Some of these problems could be extended to other Web 2.0 applications. Our major findings are: (1) Standardized application level protocols are necessary. They will enable us to develop tools capable of generating workloads for different types of web publishing systems. (2) The distributed architecture is not optional, it is necessary if we want to model scenarios happening in days or hours of heavy loads, such as flash crowds. (3) The introduction of new posts could influence the popularity of blogs. We address the question on the usefulness of popularity static models to represent the dynamism of Web 2.0 applications.