Patent ID: 9128847
Filing Date: 2015-09-08
Classification: G06F

Abstract:
1. A cache control apparatus comprising: a primary cache part; a secondary cache part configured to cache data destaged from the primary cache part; and a controller connected to the primary cache part and to the secondary cache part, wherein the secondary cache part includes a first storage part and a second storage part having a lifetime longer than that of the first storage part; and the controller is configured to determine whether the data destaged from the primary cache part is to be stored in the first storage part or the second storage part in the secondary cache part, based on a use state indicating whether the data has been updated, and to store the data in the first storage part or the second storage part determined; the controller is configured to determine whether a read count of the data is equal to or larger than a predetermined threshold when the data is destaged from the second storage part in the secondary cache part; the controller is configured to migrate the data in the second storage part into the first storage part when the read count is equal to or larger than the predetermined threshold, and to invalidate the data in the second storage part when the read count is smaller than the threshold; and the controller is configured to merge data read from the first storage part and data read from the second storage part and to transfer the merged data to a place from which a read request is received, when the data to be read according to the read request has been stored by being distributed to the first storage part and the second storage part in the secondary cache part.