Patent ID: 8549388
Filing Date: 2013-10-01
Classification: G06F

Abstract:
1. A controller that controls writing into a first data-storage unit and a second data-storage unit included in a storage apparatus, and reading from the first data-storage unit and the second data-storage unit, the second data-storage unit storing user data of which writing is requested by a host device and parity data of the user data, the first data-storage unit storing the parity data, a storage area in the second data-storage unit in which user data is stored having a first state and a second state, the first state being a state that user data stored in the storage area is protected by the parity data stored by the first data-storage unit, the second state being a state that user data stored in the storage area is not protected by the parity data stored by the first data-storage unit, the controller comprising: a parity updating unit that updates the parity data when the state of the storage area is changed, and writes first parity data into the first data-storage unit, the first parity data being the updated parity data; and a parity writing unit that reads the parity data written in the first data-storage unit and writes second parity data into the second data-storage unit at a timing determined independently from the timing of updating of the parity data, the second parity data being the read parity data.