Evolution of LCG-2 Data Management
Jean-Philippe Baud, Casey, J · CERN Document Server (European Organization for Nuclear Research) · 2005
The LCG-2 middleware was used in the spring 2004 data challenges by all four LHC experiments.This produced the first useful feedback on scalability and functionality problems in the middleware, especially with regards to data management.In light of the feedback from the data challenges, and in conjunction with the LHC experiments, a strategy for the improvements required in the data management area was developed.The aim of these improvements was to allow both easier interaction and better performance from the experiment frameworks and other middleware such as POOL.In this paper, we will cover the problems and issues highlighted by the data challenges, as well as the required improvements to allow LCG-2 to handle effectively data management at LHC volumes.In particular, we will highlight the new and improved services provided. EXPERIMENT FEEDBACK FROM DATA CHALLENGESThe data challenges in 2004 was the first real experiment production use of LCG-2.During the course of the data challenges, many issues and problems were exposed that had not shown up before in more limited tests.The deployment, service and development teams worked closely with the experiments to understand these issues.Some of the problems were solved during the data challenges, with new versions of software being deployed in agreement with the experiments during the data challenge.Other problems required more work to resolve, and indeed some exposed fundamental problems with the middleware as deployed in LCG-2.The problems within the data management software can be broken down into two main areas -performance problems and missing functionality.