IT Infrastructure Design and Implementation Considerations for the ATLAS TDAQ System

This paper gives a thorough overview of the ATLAS TDAQ SysAdmin group activities which deals with administration of the TDAQ computing environment supporting Front End detector hardware, Data Flow, Event Filter and other subsystems of the ATLAS detector operating on the LHC accelerator at CERN. The current installation consists of approximately 1500 netbooted nodes managed by more than 60 dedicated servers, a high performance centralized storage system, about 50 multi‐screen user interface systems installed in the control rooms and various hardware and critical service monitoring machines. In the final configuration, the online computer farm will be capable of hosting tens of thousands applications running simultaneously. The ATLAS TDAQ computing environment is now serving more than 3000 users subdivided into approximately 300 categories in correspondence with their roles in the system. The access and role management system is custom built on top of an LDAP schema. The engineering infrastructure of the ATLAS experiment provides 340 racks for hardware components and 4 MW of cooling capacity. The estimated data flow rate exported by the ATLAS TDAQ system for future long term analysis is about 2.5 PB/year. The number of CPU cores installed in the system will exceed 10000 during 2010.