Models for replica synchronisation and consistency in a data grid Dullmann, D.; Hoschek, W.; Jaen-Martinez, J. ...
High Performance Distributed Computing: Proceedings of the 10th IEEE International Symposium on High Performance Distributed Computing; 07-09 Aug. 2001,
01/2001
Conference Proceeding, Journal Article
Data grids are currently proposed solutions to large-scale data management problems, including efficient file transfer and replication. Large amounts of data and the world-wide distribution of data ...stores contribute to the complexity of the data management challenge. Recent architecture proposals and prototypes deal with replication of read-only files but do not address the replica synchronisation problem. We propose a new data grid service, called the Grid Consistency Service (GCS), that sits on top of existing data grid services and allows for replica update synchronisation and consistency maintenance. We give models for different levels of consistency, provided to the Grid user and discuss how they can be included into a replica consistency service for a data grid.
In wide area computing systems, it is often desirable to create remote read-only copies (replicas) of files. Replication can be used to reduce access latency, improve data locality, and/or increase ...robustness, scalability and performance for distributed applications. We define a replica location service (RLS) as a system that maintains and provides access to information about the physical locations of copies. An RLS typically functions as one component of a data grid architecture. This paper makes the following contributions. First, we characterize RLS requirements. Next, we describe a parameterized architectural framework, which we name Giggle (for GIGa-scale Global Location Engine), within which a wide range of RLSs can be defined. We define several concrete instantiations of this framework with different performance characteristics. Finally, we present initial performance results for an RLS prototype, demonstrating that RLS systems can be constructed that meet performance goals.
In this paper, we propose the Web Service Discovery Architecture (WSDA). At runtime, Grid applications can use this architecture to discover and adapt to remote services. WSDA promotes an ...interoperable web service discovery layer by defining appropriate services, interfaces, operations and protocol bindings, based on industry standards. It is unified because it subsumes an array of disparate concepts, interfaces and protocols under a single semi-transparent umbrella. It is modular because it defines a small set of orthogonal multi-purpose communication primitives (building blocks) for discovery. These primitives cover service identification, service description retrieval, data publication as well as minimal and powerful query support. The architecture is open and flexible because each primitive can be used, implemented, customized and extended in many ways. It is powerful because the individual primitives can be combined and plugged together by specific clients and services to yield a wide range of behaviors and emerging synergies.
Within the European DataGrid project, Work Package 2 has designed and implemented a set of integrated replica management services for use by data intensive scientific applications. These services, ...based on the web services model, enable movement and replication of data at high speed from one geographical site to another, management of distributed replicated data, optimization of access to data, and the provision of a metadata management tool. In this paper we describe the architecture and implementation of these services and evaluate their performance under demanding Grid conditions.
Several boundary element formulations using the electric and magnetic field vectors are presented for eddy current problems. The robustness and the accuracy of the numerical approach depending on the ...frequency and the material properties of the eddy current region are investigated. Numerical results of a conducting sphere model are compared with analytical solutions. In additional examples the treatment of structures containing geometrical singularities (ideal edges and corners) is shown and numerical results are presented.< >
A new method for the evaluation of singular boundary element integrals over three-dimensional isoparametric boundary elements of higher order is presented. This new procedure represents a Gaussian ...quadrature technique using polar coordinates for the calculation of the Gaussian points and the weighting coefficients. This method permits an efficient integration of singular kernels of order O(1/r) on curved surfaces. For a numerical example the proposed integration scheme is compared with other methods (subdivision technique, double exponential formula method, modified Gauss-quadrature) showing high efficiency and accuracy. The actual computation can be easily included in any existing computer code.
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