CARA
The large-scale research facility 'Computer for Advanced Research in Aerospace' (CARA) is used to carry out numerical simulations. When questions of design and optimisation are transferred into mathematical equations, high-performance computing is required to approach possible solutions. For example, the aerodynamic drag experienced by cars or trains, or the stall and wake turbulence of aircraft. The optimal placement of wind turbines or the tuning of combustion processes targeted at specific goals, such as exhaust gas composition or energy input, can also be simulated with this high-performance computing cluster.
CARA can be used as the first pillar of support – alongside CARO in Göttingen – by all DLR institutes to solve problems for which conventional personal computers or servers are not powerful enough. The staff of the Centre for Information Services and High Performance Computing (Zentrum für Informationsdienste und Hochleistungsrechnen; ZIH) operate the cluster for DLR and manage access to the supercomputer. By concentrating on the provision of just a few HPC clusters for a wide range of potential users, a high level of effectiveness and efficiency is achieved.
CARA is a very powerful high-performance computing cluster. It has 2280 nodes and is equipped with AMD EPYC processors, each with two sockets and 32 computing cores. The system is water-cooled and has a power consumption of up to 1.2 megawatts. The storage components are divided into 16.5 petabytes of hard disk drive (HDD) and 0.5 petabytes of solid state drive (SSD). CARA has a maximum computing power of 2.568 trillion computing operations per second. Currently, 552 additional CPU nodes and 10 GPU nodes are being added to the system. 112 of the previous Naples processors are being replaced with AMD EPYC Rome 7702, each with 64 processing cores. The system’s specifications were designed with the requirements of a broad spectrum of uses at DLR in mind.
In addition to numerical simulations, the HPC Cluster is also used to run AI applications and carry out data analyses. The operation of the system within the Lehmann Data Centre (Lehmann-Zentrum Rechnen; LZR) of TU Dresden marks an important milestone in DLR history. The organisation is no longer accessing high-performance computers through a service provider, but is rather once again investing in high-performance computing facilities that are available to all DLR institutes after almost 20years of leasing equipment.
The many years of experience and expertise of the Faculty of Computer Science at TU Dresden and the ZIH located there are important for the system's operation. The data storage space at LZR and the building infrastructure (power supply, cooling, building automation, etc.) are rented from the Free State of Saxony, represented by Public Enterprise Saxon Property and Construction Management (Staatsbetrieb Sächsisches Immobilien- und Baumanagement). The data centre currently meets the highest energy efficiency requirements. A very low power usage effectiveness (PUE) value of 1.2 can be achieved by cooling the system using water at a relatively high temperature. In the future, the waste heat from CARA will be used to heat the new building of the DLR Institute of Software Methods for Product Virtualization, which is currently under construction just 30 metres to the north.