A data collation method in a storage array including reading first data from a first logical address without decompression, assigning, by a storage controller, a second logical address to the first data, storing the first data to the second logical address, establishing, by the storage controller, a mapping relationship between an address of a storage array and the second logical address, where the first logical address is mapped to a first physical address of a storage device, a length of the first physical address is equal to a length of first data, a length of the first logical address is equal to a length of second data, and the first data is compressed data of the second data, and receiving, by the storage controller, the first data from the storage device.