Section: 18.4 The Cache in NetCDF-4

18.4 The Cache in NetCDF-4

The cache is used when reading or writing data. Set the cache size correctly for each variable to improve performance.

Starting in 4.0.1, netCDF allows user to specify chunk cache size for the file.
The cache size for data transfers in HDF5 is 1 MB, by default. This is small for many real applications, so netCDF-4 uses a default cache size of 32 MB.
The default cache size for netCDF-4 can be changed at configure time.
Set the cache size so that it can hold multiple chunks of data. If your chunk size is less than your cache size, performance will suffer.
This does not get set permanently for the variable, it only lasts as long as the file is open.