A Redundant Array of Independent Disks (RAID) controller receives new data that is to be written, wherein the new data is indicated in blocks of a first block size. The RAID controller reads old data, and old parity that corresponds to the old data, stored in blocks of a second block size that is larger in size than the first block size. The RAID controller computes new parity based on the new data, the old data, and the old parity. The RAID controller writes the new data and the new parity aligned to the blocks of the second block size, wherein portions of the old data that are not overwritten by the RAID controller are also written to the blocks of the second block size.