Moin, we have recently discovered performance problems on our parallel scratch file system (fhgfs) in a 400-node-cluster. Much of the blame went to my quantum espresso jobs (custom-patched 4.3.2). I am performing calculations on thousands of small crystals, most having no symmetry, leading to a huge number of irreducable k-points. At least in this version, QE/iotk creates one directory per k-point, with only one small file (eigenval.xml) contained in it. Even if I set '&system::disk_io="low"', this behaviour seems to have a major impact on the overall performance of the file system.
Are there any plans to move away from the 'many-small-files' paradigm? Or is there any way/switch to make QE use another scheme for the scratch files? -- Mit freundlichen Gr??en Henning Glawe Max-Planck-Institut f?r Mikrostrukturphysik Weinberg 2, 06120 Halle (Saale), Germany http://www.mpi-halle.de/~theory Phone: +49-345-5582-613 Fax: +49-345-5511223 Email: glawe at mpi-halle.de
