1. A method for accelerating data access, performed by a computer system having one or more processors, memory, a tiered data structure stored in the memory, the tiered data structure comprising a plurality of tiers, and a persistent cache for storing accelerated data, the method comprising: receiving, at the computer system, data access commands from two or more clients to access data in objects identified by the data access commands; processing, by the computer system, the data access commands to update access history information for respective object portions of the objects identified by the data access commands from the two or more clients, wherein the processing includes: in accordance with the access history information, determining usage rates for each of the respective object portions identified by the data access commands, and assigning each of the respective object portions identified by the data access commands to one of the plurality of tiers within the tiered data structure in accordance with a determination that a respective determined usage rate for a respective object portion is within a range of usage rates for a respective tier to which the respective object portion is assigned; wherein each tier of the plurality of tiers within the tiered data structure stores information identifying object portions assigned to that tier; automatically identifying and marking for acceleration at least some of the respective object portions identified by the data access commands from the two or more clients in accordance with respective tiers to which the at least some of the respective object portions have been assigned, wherein the automatically identifying and marking are performed collectively for the at least some of the respective object portions identified by the data access commands from the two or more clients; and accelerating data access to the at least some of the respective object portions marked for acceleration, by writing the at least some respective object portions marked for acceleration to the persistent cache; wherein the persistent cache is shared by the two or more clients.