The first exa-scale supercomputers are expected to be operational in China, USA, Japan and Europe within the early 2020’s. This allows scientists to execute applications at extreme scale with more than 1018 floating point operations per second (exa-FLOPS). However, the number of FLOPS is not the only parameter that determines the final performance. In order to store intermediate results or to provide fault tolerance, most applications need to perform a considerable amount of I/O operations during runtime. The performance of those operations is determined by the throughput from volatile (e.g. DRAM) to non-volatile stable storage. Regarding the slow growth in network bandwidth compared to the computing capacity on the nodes, it is highly beneficial to deploy local stable storage such as the new non-volatile memories (NVMe), in order to avoid the transfer through the network to the parallel file system. In this work, we analyse the performance of three different storage levels of the CTE-POWER9 cluster, located at the Barcelona Supercomputing Center (BSC). We compare the throughputs of SSD, NVMe on the nodes to the GPFS under various scenarios and settings. We measured a maximum performance on 16 nodes of 83 GB/s using NVMe devices, 5.6 GB/s for SSD devices and 4.4 GB/s for writes to the GPFS.

This project has received funding from the European Union’sHorizon 2020 research and innovation programme under the Marie Sklodowska-Curiegrant agreement No 708566 (DURO). Part of the research presented here has receivedfunding from the European Union’s Seventh Framework Programme (FP7/2007-2013)and the Horizon 2020 (H2020) funding framework under grant agreement no. H2020-FETHPC-754304 (DEEP-EST). The present publication reflects only the authors’views. The European Commission is not liable for any use that might be made ofthe information contained therein.

Peer Reviewed