According to one embodiment, a storage system includes a controller. The controller receives, from a host, a write command including a block address indicating a first block in a plurality of blocks, and a page address indicating a first page of the first block. The controller writes data designated by the write command to the first page of the first block. The controller notifies the host 2 of a page address indicating a latest readable page which is included in pages of the first block, the pages containing data which was written by the host before the designated data was written to the first page, the latest readable page having become readable by writing the designated data to the first page.