CERN Accelerating science

CMS Note
Report number	CMS-CR-2009-110
Title	Ensuring Data Consistency Over CMS Distributed Computing System
Author(s)	Rossman, Paul (Fermilab)
Collaboration	on behalf of the CMS Computing and Offline Projects
Submitted to	17th International Conference on Computing in High Energy and Nuclear Physics, Prague, Czech Republic, 21 - 27 Mar 2009
Submitted by	15 May 2009
Subject category	Detectors and Experimental Techniques
Accelerator/Facility, Experiment	CERN LHC ; CMS
Free keywords	COMPUTING
Abstract	CMS utilizes a distributed infrastructure of computing centers to custodially store data, to provide organized processing resources, and to provide analysis computing resources for users. Integrated over the whole system, even in the first year of data taking, the available disk storage approaches 10 petabytes of space. Maintaining consistency between the data bookkeeping, the data transfer system, and physical storage is an interesting technical and operations challenge. In this paper we will discuss the CMS effort to ensure that data is consistently available at all computing centers. We will discuss the technical tools that monitor the consistency of the catalogs and the physical storage as well as the operations model used to find and solve inconsistencies.
Copyright/License	Preprint: (License: CC-BY-4.0)