Parity generating information processing system

An information processing system including a processor and a memory and performing data input/output with respect to a storage device, wherein

• the memory includes a buffer area and a cache area,
• the processor is configured to perform a write process,
• the write process includes
• storing new data associated with a received write request in the memory,
• reading old data updated by the new data and an old parity according to the old data from the storage device,
• storing the old data and the old parity in the memory,
• generating, based on the new data, the old data, and the old parity, a new parity according to the new data,
• storing the new parity in the memory, and
• storing the new data and the new parity in the storage device,
• wherein the processor is further configured to perform a first write process where the new data is to be stored in the buffer area or a second write process where the new data is to be stored in the cache area, and
• when receiving a read request of the new data while the first write process is in progress, the processor performs the second write process instead of the first write process, and transmits, to a request source of the received read request, new data stored in the cache area in the performed second write process.