Virtual Circuits in PhEDEx, an update from the ANSE project

The ANSE project has been working with the CMS and ATLAS experiments to bring network awareness into their middleware stacks. For CMS, this means enabling control of virtual network circuits in PhEDEx, the CMS data-transfer management system. PhEDEx orchestrates the transfer of data around the CMS experiment to the tune of 1 PB per week spread over about 70 sites. The goal of ANSE is to improve the overall working efficiency of the experiments, by enabling more deterministic time to completion for a designated set of data transfers, through the use of end-to-end dynamic virtual circuits with guaranteed bandwidth. ANSE has enhanced PhEDEx, allowing it to create, use and destroy circuits according to it's own needs. PhEDEx can now decide if a circuit is worth creating based on its current workload and past transfer history, which allows circuits to be created only when they will be useful. This paper reports on the progress made by ANSE in PhEDEx. We show how PhEDEx is now capable of using virtual circuits as a production-quality service, and describe how the mechanism it uses can be refactored for use in other software domains. We present first results of transfers between CMS sites using this mechanism, and report on the stability and performance of PhEDEx when using virtual circuits. The ability to use dynamic virtual circuits for prioritised large-scale data transfers over shared global network infrastructures represents an important new capability and opens many possibilities. The experience we have gained with ANSE is being incorporated in an evolving picture of future LHC Computing Models, in which the network is considered as an explicit component. Finally, we describe the remaining work to be done by ANSE in PhEDEx, and discuss future directions for continued development

CMS Software Distribution on the LCG and OSG Grids

The efficient exploitation of worldwide distributed storage and computing resources available in the grids require a robust, transparent and fast deployment of experiment specific software. The approach followed by the CMS experiment at CERN in order to enable Monte-Carlo simulations, data analysis and software development in an international collaboration is presented. The current status and future improvement plans are described.Comment: 4 pages, 1 figure, latex with hyperref

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

Using Linux PCs in DAQ applications

ATLAS Data Acquisition/Event Filter "-1" (DAQ/EF1) project provides the opportunity to explore the use of commodity hardware (PCs) and Open Source Software (Linux) in DAQ applications. In DAQ/EF-1 there is an element called the LDAQ which is responsible for providing local run-control, error-handling and reporting for a number of read- out modules in front end crates. This element is also responsible for providing event data for monitoring and for the interface with the global control and monitoring system (Back-End). We present the results of an evaluation of the Linux operating system made in the context of DAQ/EF-1 where there are no strong real-time requirements. We also report on our experience in implementing the LDAQ on a VMEbus based PC (the VMIVME-7587) and a desktop PC linked to VMEbus with a Bit3 interface both running Linux. We then present the problems encountered during the integration with VMEbus, the status of the LDAQ implementation and draw some conclusions on the use of Linux in DAQ applications. (18 refs)

Experience with fibre channel in the environment of the ATLAS DAQ protoype "-1" project

Fibre Channel equipment has been evaluated in the environment of the ATLAS DAQ prototype "-1". Fibre Channel PCI and PMC cards have been tested on PwerPC-based VME processor boards running LynxOS and on Pentium-based personal computers running Windows NT. The performance in terms of overhead and bandwidth has been measured in point-to-point, arbitrated loop and fabric configuration with a Fibre Ch annel switch. The possible used of the equipment for event building in the ATLAS DAQ prototype "-1" has been studied

Performance of the CMS Cathode Strip Chambers with Cosmic Rays

The Cathode Strip Chambers (CSCs) constitute the primary muon tracking device in the CMS endcaps. Their performance has been evaluated using data taken during a cosmic ray run in fall 2008. Measured noise levels are low, with the number of noisy channels well below 1%. Coordinate resolution was measured for all types of chambers, and fall in the range 47 microns to 243 microns. The efficiencies for local charged track triggers, for hit and for segments reconstruction were measured, and are above 99%. The timing resolution per layer is approximately 5 ns

Performance and Operation of the CMS Electromagnetic Calorimeter

The operation and general performance of the CMS electromagnetic calorimeter using cosmic-ray muons are described. These muons were recorded after the closure of the CMS detector in late 2008. The calorimeter is made of lead tungstate crystals and the overall status of the 75848 channels corresponding to the barrel and endcap detectors is reported. The stability of crucial operational parameters, such as high voltage, temperature and electronic noise, is summarised and the performance of the light monitoring system is presented

The production deployment of IPv6 on WLCG

The world is rapidly running out of IPv4 addresses; the number of IPv6 end systems connected to the internet is increasing; WLCG and the LHC experiments may soon have access to worker nodes and/or virtual machines (VMs) possessing only an IPv6 routable address. The HEPiX IPv6 Working Group has been investigating, testing and planning for dual-stack services on WLCG for several years. Following feedback from our working group, many of the storage technologies in use on WLCG have recently been made IPv6-capable. This paper presents the IPv6 requirements, tests and plans of the LHC experiments together with the tests performed on the group\u27s IPv6 test-bed. This is primarily aimed at IPv6-only worker nodes or VMs accessing several different implementations of a global dual-stack federated storage service. Finally the plans for deployment of production dual-stack WLCG services are presented