An apparatus comprising a first partition and a second partition. The first partition has a first file system comprising (i) a plurality of first clusters configured to store data having accesses faster than a first worst case data transfer rate and (ii) a dedicated space not used by the plurality of first clusters. The second partition has a second file system comprising a plurality of second clusters (i) configured to store data having accesses faster than a second worst case data transfer rate and (ii) occupying the dedicated space.