Distributed Computing Grid Experiences in CMS

The CMS experiment is currently developing a computing system capable of serving, processing and archiving the large number of events that will be generated when the CMS detector starts taking data. During 2004 CMS undertook a large scale data challenge to demonstrate the ability of the CMS computing system to cope with a sustained data-taking rate equivalent to 25% of startup rate. Its goals were: to run CMS event reconstruction at CERN for a sustained period at 25 Hz input rate; to distribute the data to several regional centers; and enable data access at those centers for analysis. Grid middleware was utilized to help complete all aspects of the challenge. To continue to provide scalable access from anywhere in the world to the data, CMS is developing a layer of software that uses Grid tools to gain access to data and resources, and that aims to provide physicists with a user friendly interface for submitting their analysis jobs. This paper describes the data challenge experience with Grid infrastructure and the current development of the CMS analysis system

AliEnFS - a Linux File System for the AliEn Grid Services

Among the services offered by the AliEn (ALICE Environment http://alien.cern.ch) Grid framework there is a virtual file catalogue to allow transparent access to distributed data-sets using various file transfer protocols. $alienfs$ (AliEn File System) integrates the AliEn file catalogue as a new file system type into the Linux kernel using LUFS, a hybrid user space file system framework (Open Source http://lufs.sourceforge.net). LUFS uses a special kernel interface level called VFS (Virtual File System Switch) to communicate via a generalised file system interface to the AliEn file system daemon. The AliEn framework is used for authentication, catalogue browsing, file registration and read/write transfer operations. A C++ API implements the generic file system operations. The goal of AliEnFS is to allow users easy interactive access to a worldwide distributed virtual file system using familiar shell commands (f.e. cp,ls,rm ...) The paper discusses general aspects of Grid File Systems, the AliEn implementation and present and future developments for the AliEn Grid File System.Comment: 9 pages, 12 figure

Grid Data Management in Action: Experience in Running and Supporting Data Management Services in the EU DataGrid Project

In the first phase of the EU DataGrid (EDG) project, a Data Management System has been implemented and provided for deployment. The components of the current EDG Testbed are: a prototype of a Replica Manager Service built around the basic services provided by Globus, a centralised Replica Catalogue to store information about physical locations of files, and the Grid Data Mirroring Package (GDMP) that is widely used in various HEP collaborations in Europe and the US for data mirroring. During this year these services have been refined and made more robust so that they are fit to be used in a pre-production environment. Application users have been using this first release of the Data Management Services for more than a year. In the paper we present the components and their interaction, our implementation and experience as well as the feedback received from our user communities. We have resolved not only issues regarding integration with other EDG service components but also many of the interoperability issues with components of our partner projects in Europe and the U.S. The paper concludes with the basic lessons learned during this operation. These conclusions provide the motivation for the architecture of the next generation of Data Management Services that will be deployed in EDG during 2003.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 9 pages, LaTeX, PSN: TUAT007 all figures are in the directory "figures

CERN openlab Whitepaper on Future IT Challenges in Scientific Research

This whitepaper describes the major IT challenges in scientific research at CERN and several other European and international research laboratories and projects. Each challenge is exemplified through a set of concrete use cases drawn from the requirements of large-scale scientific programs. The paper is based on contributions from many researchers and IT experts of the participating laboratories and also input from the existing CERN openlab industrial sponsors. The views expressed in this document are those of the individual contributors and do not necessarily reflect the view of their organisations and/or affiliates

Storage Management and Access in WLHC computing Grid

One of the big challenges in Grid computing is storage management and access. Several solutions exist to store data in a persistent way. In this work we describe our contribution within the Worldwide LHC Computing Grid project. Substantial samples of data produced by the High Energy Physics detectors at CERN are shipped for initial processing to specific large computing centers worldwide. Such centers are normally able to provide persistent storage for tens of Petabytes of data mostly on tapes. Special physics applications are used to refine and filter the data after spooling the required files from tape to disk. At smaller geographically dispersed centers, physicists perform the analysis of such data stored on disk-only caches. In this thesis we analyze the application requirements such as uniform storage management, quality of storage, POSIX-like file access, performance, etc. Furthermore, security, policy enforcement, monitoring, and accounting need to be addressed carefully in a Grid environment. We then make a survey of the multitude of storage products deployed in the WLCG infrastructure, both hardware and software. We outline the specific features, functionalities and diverse interfaces offered to users. We focus in particular on StoRM, a storage resource manager that we have designed and developed to provide an answer to specific user request for a fast and efficient Grid interface to available parallel file systems. We propose a model for the Storage Resource Management protocol for uniform storage management and access in the Grid. The black box testing methodology has been applied in order to verify the completeness of the specifications and validate the existent implementations. an extension for storage on the Grid. We finally describe and report on the results obtained

Storage Infrastructure at the INFN LHC Tier-1

In this paper we will describe the Storage Infrastructure of the INFN-CNAF Tier-1, used to store data of High Energy Physics experiments, in particular those operating at the Large Hadron Collider

Risk management in agriculture

This monograph was written to be part of the series of studies commissioned by the Ministry of Agriculture under the rubric of "State of Indian Farmer - A Millennium Study". On the basis of existing literature, this study documents the status of our knowledge on risks of agriculture and their management. Chapter 2 discusses the evidence on the nature, type and magnitude of agricultural risks. Chapter 3 discusses farmer strategies to combat risk. In addition to the mechanisms at the level of the farm household, the need to cope with risk can also affect community interactions and social customs. This is examined in Chapter 4. In chapter 5, we consider how production risks have been transformed by developments in the agricultural economy in the post-independence period. In chapter 6, we review the principal developments that have impacted on market risks.

The external water footprint of the Netherlands: quantification and impact assessment

This study quantifies the external water footprint of the Netherlands by partner country and import product and assesses the impact of this footprint by contrasting the geographically explicit water footprint with water scarcity in the different parts of the world. Hotspots are identified as the places where the external water footprint of Dutch consumers is significant on the one hand and where water scarcity is serious on the other hand.\ud The study shows that Dutch consumption implies the use of water resources throughout the world, with significant impacts at specified locations. This knowledge is relevant for consumers, government and businesses when addressing the sustainability of consumer behaviour and supply chains. The results of this study can be an input to bilateral cooperation between the Netherlands and the Dutch trade partners aimed at the reduction of the negative impacts of Dutch consumption on foreign water resources. Dutch government can also engage with businesses in order to stimulate them to review the sustainability of their supply chains

DIRAC - Distributed Infrastructure with Remote Agent Control

This paper describes DIRAC, the LHCb Monte Carlo production system. DIRAC has a client/server architecture based on: Compute elements distributed among the collaborating institutes; Databases for production management, bookkeeping (the metadata catalogue) and software configuration; Monitoring and cataloguing services for updating and accessing the databases. Locally installed software agents implemented in Python monitor the local batch queue, interrogate the production database for any outstanding production requests using the XML-RPC protocol and initiate the job submission. The agent checks and, if necessary, installs any required software automatically. After the job has processed the events, the agent transfers the output data and updates the metadata catalogue. DIRAC has been successfully installed at 18 collaborating institutes, including the DataGRID, and has been used in recent Physics Data Challenges. In the near to medium term future we must use a mixed environment with different types of grid middleware or no middleware. We describe how this flexibility has been achieved and how ubiquitously available grid middleware would improve DIRAC.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 8 pages, Word, 5 figures. PSN TUAT00