I fear that handing the data off to another process simply to save it will not actually give you any benefit. The reason for that is you have to send the 2.5GB of data across to the worker, which is a separate process. Sending data to a worker is in some ways equivalent to saving it to a file, and then loading it again on the worker - except that instead of a file, the "saved" data is kept in memory. Anyway. The problem you're having with parfeval is that you are sending to the worker only the name of the array that you would like to be saved, and not the data. This is because the save command itself expects to find the named variable in the calling workspace. To work around this, you need to create a tiny wrapper function. Something like this:
function saveData(fname, data, varargin)
save(fname, 'data', varargin{:});
end
which then you can use like so:
parfeval(@saveData, 0, 'full_path', largeArray, '-v7.3')
