Memory Usage

The fimex command line utility uses memory usually as one unlimited-dimension slice size, and this often copied between different buffers, so minimum memory-usage is that slice multiplied with 2 or 3.

Interpolation needs a interpolation-cache with the horizontal resolution times 5 when vector-reprojection is used.

NetCDF4/hdf5 uses a hdf chunk cache of size 1009*4M (10*4M per variable) (as default in netcdf-4.3.0). The environment-variable FIMEX_CHUNK_CACHE_SIZE changes that size, e.g. FIMEX_CHUNK_CACHE_SIZE=2185232384 will set the global cache to 521*4M (4M=4194304), and a size of 0 disables the cache (and as long as complete/compressed chunks are read, usually without preformance-degradations). The number of slots can be changed by FIMEX_CHUNK_CACHE_SLOTS, and they default to 521. Good values are large primes, much larger than the number of chunks.