A data processing method in a storage system and the storage system, and relates to the field of data storage technologies. A client first sends a data block in a stripe and metadata of the data block to a data storage node. The client then sends the metadata of the data block and a parity block to a parity storage node, to back up the metadata of the data block on the parity storage node. When the metadata of the data block is successfully backed up, the data block is written into a corresponding storage device based on a storage location indicated by the metadata. This reduces write operation time.