Update atlas.tex

contributions/atlas/atlas.tex

@@ -35,9 +35,9 @@ The Athena framework is an enhanced version of the Gaudi framework that was orig
 design principles are the clear separation of data and algorithms, and between transient (in-memory) and persistent (in-file) data. All levels of processing of ATLAS data, from high-level trigger to event simulation, reconstruction and analysis, take place within the Athena framework; in this way it is easier for code developers and users to test and run algorithmic code, with the assurance that all geometry and conditions data will be the same for all types of applications ( simulation, reconstruction, analysis, visualization).
 One of the principal challenges for ATLAS computing is to develop and operate a data storage and management infrastructure able to meet the demands of a yearly data volume of O(10PB) utilized by data processing and analysis activities spread around the world.  The ATLAS Computing Model establishes the environment and operational requirements that ATLAS data-handling systems must support and provides the primary guidance for the development of the data management systems.
 The ATLAS Databases and Data Management Project (DB Project) leads and coordinates ATLAS activities in these areas, with a scope encompassing technical data bases (detector production, installation and survey data), detector geometry, online/TDAQ databases, conditions databases (online and offline), event data, offline processing configuration and bookkeeping, distributed data management, and distributed database and data management services. The project is responsible for ensuring the coherent development, integration and operational capability of the distributed database and data management software and infrastructure for ATLAS across these areas.
-The ATLAS Computing Model defines the distribution of raw and processed data to Tier 1 and Tier 2 centres, so as to be able to exploit fully the computing resources that are made available to the Collaboration. Additional computing resources are available for data processing and analysis at Tier-3 centres and other computing facilities to which ATLAS may have access. A complex set of tools and distributed services, enabling the automatic distribution and processing of the large amounts of data, has been developed and deployed by ATLAS in cooperation with the LHC Computing Grid (LCG) Project and with the middleware providers of the three large Grid infrastructures we use: EGI, OSG and NorduGrid. The tools are designed in a flexible way, in order to have the possibility to extend them to use other types of Grid middleware in the future.
-The main computing operations that ATLAS have to run comprise the preparation, distribution and validation of ATLAS software, and the computing and data management operations run centrally on Tier-0, Tier-1s and Tier-2s. The ATLAS Virtual Organization allows production and analysis users to run jobs and access data at remote sites using the ATLAS-developed Grid tools.
-The Computing Model, together with the knowledge of the resources needed to store and process each ATLAS event, gives rise to estimates of required resources that can be used to design and set up the various facilities. It is not assumed that all Tier-1s or Tier-2s are of the same size; however, in order to ensure a smooth operation of the Computing Model, all Tier-1s usually have broadly similar proportions of disk, tape and CPU, and similarly for the Tier-2s.
+The ATLAS Computing Model defines the distribution of raw and processed data to Tier 1 and Tier 2 centres, so as to be able to exploit fully the computing resources that are made available to the Collaboration. Additional computing resources are available for data processing and analysis at Tier 3 centres and other computing facilities to which ATLAS may have access. A complex set of tools and distributed services, enabling the automatic distribution and processing of the large amounts of data, has been developed and deployed by ATLAS in cooperation with the LHC Computing Grid (LCG) Project and with the middleware providers of the three large Grid infrastructures we use: EGI, OSG and NorduGrid. The tools are designed in a flexible way, in order to have the possibility to extend them to use other types of Grid middleware in the future.
+The main computing operations that ATLAS have to run comprise the preparation, distribution and validation of ATLAS software, and the computing and data management operations run centrally on Tier 0, Tier 1 sites and Tier 2 sites. The ATLAS Virtual Organization allows production and analysis users to run jobs and access data at remote sites using the ATLAS-developed Grid tools.
+The Computing Model, together with the knowledge of the resources needed to store and process each ATLAS event, gives rise to estimates of required resources that can be used to design and set up the various facilities. It is not assumed that all Tier 1 sites or Tier 2 sites are of the same size; however, in order to ensure a smooth operation of the Computing Model, all Tier 1 centres usually have broadly similar proportions of disk, tape and CPU, and similarly for the Tier 2 sites.
 The organization of the ATLAS Software and Computing Project reflects all areas of activity within the project itself. Strong high-level links are established with other parts of the ATLAS organization, such as the TDAQ Project and Physics Coordination, through cross-representation in the respective steering boards. The Computing Management
 Board, and in particular the Planning Officer, acts to make sure that software and computing developments take place coherently across sub-systems and that the project as a whole meets its milestones. The International Computing Board assures the information flow between the ATLAS Software and Computing Project and the national resources and their Funding Agencies.
 
@@ -45,8 +45,8 @@ Board, and in particular the Planning Officer, acts to make sure that software a
 
 \section{The role of the Italian Computing facilities in the global ATLAS Computing}
 
-Italy provides Tier-1, Tier-2 and Tier-3 facilities to the ATLAS collaboration. The Tier-1, located at CNAF, Bologna, is the main centre, also referred as “regional” centre. The Tier 2 centres are distributed in different areas of Italy, namely in Frascati, Napoli, Milano and Roma. All 4 Tier 2 sites are considered as Direct Tier 2 (T2D), meaning that they have an higher importance with respect to normal Tier 2s and can have primary data too. They are also considered satellites of the Tier 1, also identified as nucleus. The total of the Tier 2 sites corresponds to more than the total ATLAS size at the Tier 1, for what concerns disk and CPUs; tape is not available in the Tier 2 sites. A third category of sites is the so-called Tier 3 centres. Those are smaller centres, scattered in different places in Italy, that nevertheless contributes in a consistent way to the overall computing power, in terms of disk and CPUs. The overall size of the Tier 3 sites corresponds roughly to the size of a Tier-2 site. The Tier-1 and Tier-2 sites have pledged resources, while the Tier-3 sites do not have any pledge resource available.
-In terms of pledged resources, Italy contributes to the ATLAS computing as 9\% of both CPU and disk for the Tier-1. The share of the Tier-2 facilities corresponds to 7\% of disk and 9\% of CPU of the whole ATLAS computing infrastructure. The Italian Tier-1, together with the other Italian centres, provides both resources and expertise to the ATLAS computing community, and manages the so-called Italian Cloud of computing. Since 2015 the Italian Cloud does not only include Italian sites, but also Tier 3 sites of other countries, namely South Africa and Greece.
+Italy provides Tier 1, Tier 2 and Tier 3 facilities to the ATLAS collaboration. The Tier 1, located at CNAF, Bologna, is the main centre, also referred as “regional” centre. The Tier 2 centres are distributed in different areas of Italy, namely in Frascati, Napoli, Milano and Roma. All 4 Tier 2 sites are considered as Direct Tier 2 (T2D), meaning that they have an higher importance with respect to normal Tier 2s and can have primary data too. They are also considered satellites of the Tier 1, also identified as nucleus. The total of the Tier 2 sites corresponds to more than the total ATLAS size at the Tier 1, for what concerns disk and CPUs; tape is not available in the Tier 2 sites. A third category of sites is the so-called Tier 3 centres. Those are smaller centres, scattered in different places in Italy, that nevertheless contributes in a consistent way to the overall computing power, in terms of disk and CPUs. The overall size of the Tier 3 sites corresponds roughly to the size of a Tier 2 site. The Tier 1 and Tier 2 sites have pledged resources, while the Tier-3 sites do not have any pledge resource available.
+In terms of pledged resources, Italy contributes to the ATLAS computing as 9\% of both CPU and disk for the Tier 1. The share of the Tier 2 facilities corresponds to 7\% of disk and 9\% of CPU of the whole ATLAS computing infrastructure. The Italian Tier 1, together with the other Italian centres, provides both resources and expertise to the ATLAS computing community, and manages the so-called Italian Cloud of computing. Since 2015 the Italian Cloud does not only include Italian sites, but also Tier 3 sites of other countries, namely South Africa and Greece.
 The computing resources, in terms of disk, tape and CPU, available in the Tier 1 at CNAF have been very important for all kind of activities, including event generation, simulation, reconstruction, reprocessing and analysis, for both MonteCarlo and real data. Its major contribution has been the data reprocessing, since this is a very I/O and memory intense operation, normally executed only in Tier 1 centres. In this sense CNAF has played a fundamental role for the fine measurement of the Higgs [3] properties in 2018 and other analysis. The Italian centres, including CNAF, have been very active not only in the operation side, but contributed a lot in various aspect of the Computing of the ATLAS experiment, in particular for what concerns the network, the storage systems, the storage federations and the monitoring tools. The Tier 1 at CNAF has been very important for the ATLAS community in 2018, for some specific activities:
 
 \begin{itemize}
@@ -58,9 +58,9 @@ The computing resources, in terms of disk, tape and CPU, available in the Tier 1
 
 \section{Main achievements of ATLAS Computing centers in Italy}
 
-The Italian Tier-2 Federation runs all the ATLAS computing activities in the Italian cloud supporting the operations at CNAF, the Italian Tier-1 centre, and the Milano, Napoli, Roma1 and Frascati Tier-2 sites. This insures an optimized use of the resources and a fair and efficient data access.  The computing activities of the ATLAS collaboration have been constantly carried out over the whole 2018, in order to analyse the data of the Run-2 and produce the Monte Carlo data needed for the 2018 run.
+The Italian Tier 2 Federation runs all the ATLAS computing activities in the Italian cloud supporting the operations at CNAF, the Italian Tier 1 centre, and the Milano, Napoli, Roma1 and Frascati Tier 2 sites. This insures an optimized use of the resources and a fair and efficient data access.  The computing activities of the ATLAS collaboration have been constantly carried out over the whole 2018, in order to analyse the data of the Run-2 and produce the Monte Carlo data needed for the 2018 run.
  
-The LHC data taking started in April 2018 and, until the end of the operation in December 2018, all the Italian sites, the CNAF Tier-1 and the four Tier-2s, have been involved in all the computing operations of the collaboration: data reconstruction, Monte Carlo simulation, user and group analysis and data transfer among all the sites. Besides these activities, the Italian centers have contributed to the upgrade of the Computing Model both from the testing side and the development of specific working groups. ATLAS collected and registered at the Tier-0 ~60.6 fb$^{-1}$ and ~25 PB of raw and derived data, while the cumulative data volume distributed in all the data centers in the grid was of the order of ~80 PB. The data has been replicated with an efficiency of 100\% and an average throughput of the order of ~13 GB/s during the data taking period, with peaks above 25 GB/s. For just Italy, the average throughput was of the order of 800 MB/s with peaks above 2GB/s. The data replication speed from Tier-0 to the Tier-2s has been quite fast with a transfer time lower than 4 hours. The average number of simultaneous jobs running on the grid has been of about 110k for production (simulation and reconstruction) and data analysis, with peaks over 150k, with an average CPU efficiency up to more than 80\%. The use of the grid for analysis has been stable on ~26k simultaneous jobs, with peaks around the conferences’ periods to over 40k, showing the reliability and effectiveness of the use of grid tools for data analysis.
+The LHC data taking started in April 2018 and, until the end of the operation in December 2018, all the Italian sites, the CNAF Tier 1 and the four Tier 2 sites, have been involved in all the computing operations of the collaboration: data reconstruction, Monte Carlo simulation, user and group analysis and data transfer among all the sites. Besides these activities, the Italian centers have contributed to the upgrade of the Computing Model both from the testing side and the development of specific working groups. ATLAS collected and registered at the Tier 0 ~60.6 fb$^{-1}$ and ~25 PB of raw and derived data, while the cumulative data volume distributed in all the data centers in the grid was of the order of ~80 PB. The data has been replicated with an efficiency of 100\% and an average throughput of the order of ~13 GB/s during the data taking period, with peaks above 25 GB/s. For just Italy, the average throughput was of the order of 800 MB/s with peaks above 2GB/s. The data replication speed from Tier 0 to the Tier 2 sites has been quite fast with a transfer time lower than 4 hours. The average number of simultaneous jobs running on the grid has been of about 110k for production (simulation and reconstruction) and data analysis, with peaks over 150k, with an average CPU efficiency up to more than 80\%. The use of the grid for analysis has been stable on ~26k simultaneous jobs, with peaks around the conferences’ periods to over 40k, showing the reliability and effectiveness of the use of grid tools for data analysis.
  
 The Italian sites contributed to the development of the Xrootd and http/webdav federation. In the latter case the access to the storage resources is managed using the http/webdav protocol, in collaboration with the CERN DPM team, the Belle2 experiment, the Canadian Corporate Cloud ant the RAL (UK) site. The purpose is to build a reliable storage federation, alternative to the Xrootd one, to access physics data both on the grid and on cloud storage infrastructures (like Amazon S3, MicroSoft Azure, etc). The Italian community is particularly involved in this project and the first results have been presented to the WLCG collaboration.