Motivation: Setting raw data chunk cache parameters can be done with H5P_SET_CACHE, H5P_SET_CHUNK_CACHE, or a combination of both. H5P_SET_CACHE is used to adjust the chunk cache parameters for all datasets via a global setting for the file, and H5P_SET_CHUNK_CACHE is used to adjust the chunk cache parameters for individual datasets. When both are used, parameters set with H5P_SET_CHUNK_CACHE will override any parameters set with H5P_SET_CACHE.
Optimum chunk cache parameters may vary widely depending on different data layout and access patterns. For datasets with low performance requirements for example, changing the cache settings can save memory.
Note: Raw dataset chunk caching is not currently supported when using the MPI I/O and MPI POSIX file drivers in read/write mode; see H5P_SET_FAPL_MPIO and H5P_SET_FAPL_MPIPOSIX, respectively. When using one of these file drivers, all calls to H5D_READ and H5D_WRITE will access the disk directly, and H5P_SET_CACHE will have no effect on performance.
Raw dataset chunk caching is supported when these drivers are used in read-only mode.