186 research outputs found
Introduction to CERN Computing Services
No full textIntroduction to CERN Computing Services.
The IT department is responsible for a variety of basic services and large computing resource installations. The talk will describe
these services and how they are interconnected. The focus is on the details about the data flow and processing facilities for the LHC experiments physics data
Correlation engine prototype
No full textThe CERN monitoring prototype, part of the fabric management work package (WP4) of the DataGrid project, task Monitoring, collects monitoring data from farm nodes in CERN into a central monitoring database. Performing correlations on the data in the monitoring database should help to foresee exceptions on individual nodes or node groups and to analyze performance of the farm. The Correlation Engine Prototype has been developed to provide easy adding of new correlations of monitoring data and actions triggered in case of exceptions. The current prototype is written in Perl. The results of the correlation engine can be accessed through a web-interface
The CMS CERN Analysis Facility (CAF)
No full textThe CMS CERN Analysis Facility (CAF) was primarily designed to host a large variety of latency-critical workflows. These break down into alignment and calibration, detector commissioning and diagnosis, and high-interest physics analysis requiring fast-turnaround. In addition to the low latency requirement on the batch farm, another mandatory condition is the efficient access to the RAW detector data stored at the CERN Tier-0 facility. The CMS CAF also foresees resources for interactive login by a large number of CMS collaborators located at CERN, as an entry point for their day-by-day analysis. These resources will run on a separate partition in order to protect the high-priority use-cases described above. While the CMS CAF represents only a modest fraction of the overall CMS resources on the WLCG GRID, an appropriately sized user-support service needs to be provided. We will describe the building, commissioning and operation of the CMS CAF during the year 2008. The facility was heavily and routinely used by almost 250 users during multiple commissioning and data challenge periods. It reached a CPU capacity of 1.4MSI2K and a disk capacity at the Peta byte scale. In particular, we will focus on the performances in terms of networking, disk access and job efficiency and extrapolate prospects for the upcoming LHC first year data taking. We will also present the experience gained and the limitations observed in operating such a large facility, in which well controlled workflows are combined with more chaotic type analysis by a large number of physicists
- …
