US Patent 9081716 Solid-state disk cache-assisted redundant array of independent disks

A system including a write module to receive first data for writing over second data stored on a first member of a stripe of a RAID. A read module reads the second data and first parity from a SSD or the RAID. Before receiving third data for writing over fourth data stored on a second member of the stripe, the read module reads the fourth data from the second member and stores the fourth data in the SSD. A parity module generates second parity based on the first data, the second data, and the first parity. The write module writes the second parity on the SSD. On receiving the third data, the parity module generates the third parity based on the third data, the fourth data, and the second parity.