A method of managing a plurality of files according to their respective instances of a property of the files, a data processing device that uses the method, and a computer readable storage medium bearing code for implementing the method. The files of at least one of the instances are managed according to a management protocol respective to that/those instance(s). Preferably, all the other files are managed according to a common default management protocol. Different protocols trade off performance vs. ruggedness, trade off average performance vs. latency, or include different defragmentation policies.