A system for transferring data to and from one or more slow-access-time-mass-storage nodes which store data at respective first ranges of logical block addresses (LBAs), including a plurality of interim-fast-access-time nodes which are configured to operate independently of one another. Each interim-fast-access-time node is assigned a respective second range of the LBAs and is coupled to receive data from and provide data to the one or more slow-access-time-mass-storage nodes within the respective second range.The system further includes one or more interface nodes, which are adapted to receive input/output (IO) requests from host processors directed to specified LBAs and to direct all the IO requests to the interim-fast-access-time node to which the specified LBAs are assigned.