Tuning parallel HDF5 for a specific application on a specific system requires playing with a lot of tunable parameters many of which are specific to certain platforms. Not all hints are applicable to all platforms, and some hints may be ignored even if they can be applied. The best practice here is to look at each system's webpage on how to tune I/O parameters. For example, Hopper, a Cray XE6 supercomputer at NERSC, has a webpage specifically on how to tune parallel I/O parameters for specific file systems:

http://www.nersc.gov/users/computational-systems/hopper/file-storage-and-i-o/

Here are some general parameters that users should consider tuning when they see slow I/O performance from HDF5:

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