Leandro Neumann Ciuffo

Using a Simple Prioritisation Mechanism to Effectively Interoperate Service and Opportunistic Grids in the EELA-2 e-Infrastructure

Grids currently in production can be broadly classified as either service Grids, composed of dedicated resources, or opportunistic Grids that harvest the computing power of non-dedicated resources when they are idle. While a service Grid provides high and well defined levels of quality of service, an opportunistic Grid provides only a best-effort service. Nevertheless, since opportunistic Grids do not require resources to be fully dedicated to the Grid, they have the potential to assemble a much larger number of resources. Moreover, these Grids cater very well to the execution of the so-called embarrassingly parallel applications, a type of application that is frequently found in practice, and that comprises the largest portion of the typical workload processed in production Grid systems. The EELA-2 e-infrastructure is comprised of a service Grid and an opportunistic Grid that federates computing resources from scientific institutions in both Europe and Latin America. Due to the complementary characteristics of these two types of Grids, a lot of attention has recently been placed in how to interoperate them. In this paper we focus on the less studied problem of assessing the feasibility of such interoperation. We analyse different prioritisation policies that define when the resources of one Grid can be used to run jobs originating from the other. Our results show that in the absence of a suitable prioritisation policy, the benefits that the users of one Grid may have, frequently come with an important negative impact on the users of the other Grid. We also show that a simple reciprocation mechanism is capable of arbitrating the interoperation in such a way that, whenever possible, users profit from the interoperation and, in no case, this benefit leads to a noticeable reduction on the quality of service that the users would experience were the Grids not to interoperate. We conclude discussing how we have implemented, in the context of the EELA-2 project, this prioritisation mechanism, allowing the effective interoperation of a service Grid based on the gLite middleware with an opportunistic Grid that uses the OurGrid middleware.

A Digital Library Management System for Grid

Huge amount of data can be stored on Grid Storage Elements, but few tools are provided by the EGEE gLite middleware to easily search and retrieve files a user is looking for. File catalogues can help organizing data in hierarchical structures, but they do not provide a way to describe file contents. On the other hand, we have Metadata Services, that can be used to attach additional information to files, but this services are not so easy to use by non-experienced people. In this paper a easy-to-use system to handle digital assets stored as grid file is presented. Such system is called gLibrary. It offers a intuitive interface that allow users to browse and filter the available entries, as well as to retrieve or upload a file by copying it from one of the Storage Elements (SEs) into users local machine, or vice-versa.

Increasing e-Infrastructure Usability: The EELA-2 Experience

The heterogeneous requirements of e-Science applications belonging to several scientific domains makes difficult to provide them with a support able to satisfy all the different needs. Usually, the grid middleware adopted provides applications with general tools unable to meet specific requirements. For this reason, a really powerful e-Infrastructure has to offer some additional services to complete and integrate the functionalities of the basic grid middleware. These services have both to increase the set of functionalities offered by the e-Infrastructure and to make the task of developing and deploying new applications easier. Following this methodology, EELA-2, a project co-funded by the European Commission and involving European and Latin American countries, has fully deployed 53 e-Science applications. This paper describes the services developed to achieve this outstanding result.

Performance Analysis of EGEE-like Grids in Asia and Latin America

A measure to estimate the value that Grids can provide to potential users can be obtained by assessing the resources availability, middleware overhead and infrastructure reliability incurred when running an application in a transcontinental e-Infrastructure like EGEE. Celebrating the recent MoU between EELA-2 [1] and EUAsiaGrid [2] projects, both co-funded by EC under the Seventh Framework Programme, this paper aims at providing a comparative study between their respective Grid infrastructures. Current monitoring tools provide information on the resources status. These figures are useful for Grid managers in order to check the availability of the services but not for end users because they do not provide any indication on the execution of users’ applications, such as the average job delay. In our approach, we randomly submitted 10 jobs per day during 1 week both project´s infrastructures and measured its total execution time. No special requirements were set on the JDL files and we did not carry about the level of availability of the computing resources (CEs) neither about the number of jobs concurrently running at a giving moment. We let the core Workload Management System (WMS) of each project to automatically choose which CE to submit the jobs, considering both EUAsiaGrid and EELA-2 infrastructures as single entities. The analysis of the results can be used to measure the quality of services provided by both projects to its respective user communities.