DISTRIBUTED STORAGE SYSTEM, STORAGE CONTROL METHOD AND PROGRAM

摘要

A distributed storage system, comprises: a first data storage unit that holds data in a first data structure; a second data storage unit that holds the data in a second data structure different from the first data structure; an update information holding unit that holds an update information item(s) indicating update content of the data, and if a predetermined update condition is satisfied, applies the update information item(s) to the second data storage unit and reflects the update content in the second data storage unit; an update state monitoring unit that monitors the update information item(s) held by the update information holding unit and extracts as an update state an application status of the update information item(s) to the second data storage unit; and an update condition change unit that changes the predetermined update condition based on a change command for changing the predetermined update condition, the change command being determined in accordance with the update state. In the distributed storage system holding the same data in multiple different data structures, appropriate adjustment is performed of timing reflecting data updating in a data storage unit, in accordance with change in volume and frequency of access appropriate to respective data structures.