SECOND-LEVEL RAID CACHE SPLICING

System and methods for managing I/O write requests of host systems to physical storage. A storage subsystem includes a plurality of storage devices where each storage device is configured to provide data storage. A controller is connected to the plurality of storage devices for executing the I/O write requests from the host systems and is further connected to a plurality of solid state drives in a parity RAID configuration. Non-valid portions of cache lines stored in stripes of the parity RAID configured second level cache are filled with known default values. Upon receiving an I/O write request to write new data to a non-valid portion of a cache line existing in the second level cache, the new data is spliced into the cache line and a new parity value is calculated without reading the known default values saving a read and an XOR operation.