A mass storage system including main and auxiliary storage subsystems and a controller Main storage provides physical storage space and includes non-solid-state storage devices (“NSSDs”) NSSDs provide physical locations, and main storage includes physical storage locations provided by NSSDs Controller is coupled to main storage and may be configured for mapping logical addresses to physical locations, giving rise to a logical storage space The auxiliary subsystem includes a solid-state data retention device (“SSDRD”) capable of permanently storing data and provides a physical location, giving rise to auxiliary space Controller is coupled to the auxiliary subsystem and may override a mapping of logical addresses to physical locations, with a mapping of logical address to physical locations within the auxiliary space, overriding physical storage locations Controller is adapted for loading a snapshot of the data currently stored in the overridden physical storage locations.