[Pw_forum] Performance problems due to files in outdir

[Henning Glawe]

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 Grüßen
Henning Glawe

Max-Planck-Institut für 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