Data storage system and cache data—consistency assurance method

摘要

According to one embodiment, a data storage system includes a controller which accesses a first storage device using a first module on startup and accesses the first storage device using a second module after the startup. The first module records, when the write-target data is written to the first storage device, trace information indicating the write command in a second storage device. The second module determines, when taking over a reception of a command instructing writing/reading of data from the first module, whether or not unupdated data to be updated as a result of a writing of the first module is cached in the second storage device based on the trace information, and invalidates a data block including the unupdated data when the unupdated data is cached.