Just to clarify things, compression does not work with parallel HDF5 and consequently not with parallel libsplash. 

Felix

Axel Hübl <notifications@github.com> schrieb:

>In src/picongpu/include/plugins/output/HDF5Writer.hpp:
>
>> @@ -257,8 +259,7 @@ class HDF5Writer : public ISimulationIO, public IPluginModule > desc.add_options() > ("hdf5.period", po::value<uint32_t > (&notifyFrequency)->default_value(0), "enable HDF5 IO [for each n-th step]") > ("hdf5.file", po::value<std::string > (&filename)->default_value(filename), "HDF5 output file") > - ("hdf5.compression", po::value<bool > (&compression)->zero_tokens(), "enable HDF5 compression") > - ("hdf5.continue", po::value<bool > (&continueFile)->zero_tokens(), "continue existing HDF5 file instead of creating a new one"); > + ("hdf5.compression", po::value<bool > (&compression)->zero_tokens(), "enable HDF5 compression"); 
>
>I just realized that compression should be enabled by default since it usually saves a factor of 3-10 on the disks.
>Our hdd space is usually quite rare & slow and the zlib performance impact is negligible. I would change the option to nocompression = false by default.
>
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