Comment (by Roland Haas):

The same issue in IODF5 was addressed in git hash ebba415e "CarpetIOHDF5: Optimize lower-dimensional output -- only transfer necessary data to the I/O process" of carpet and most likely (given that the two thorns started out as being somewhat similar) could be applied here as well.

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/1626/carpetioascci-transfers-too-much-data-for