Patent ID: 8806134

Claim:
A method of cache data redundancy, comprising: providing a plurality of cache devices, wherein each of the plurality of cache devices is partitioned into a first allocated area and a second allocated area, the first allocated area being used for storing data items that are in an unmodified form and the second allocated area being used for storing data items that are in a modified form; copying a data item from a data source to the first allocated area in one of the plurality of cache devices, the data item being in the unmodified form; in response to the data item being modified by a data consumer, (a) logically removing the data item from the first allocated area of one of the plurality of cache devices; (b) copying the data item in the modified form to the second allocated area in one of the plurality of cache devices; and transferring the data item in the modified form from the second allocated area of one of the plurality of cache devices to the data source, in response to the transferring to the data source, copying the data item in the modified form from the second allocated area of the one of the plurality of cache devices to the first allocated area of one of the plurality of cache devices.