Application relates to storage technologies, and in particular, to writing data in a storage system having solid state disks. Embodiments of the application provide an array controller, including a communication interface and a processor. The processor receives information about a logical block from a solid state disk. The information about the logical block includes a size of the logical block and indication information of the logical block, and the logical block includes one or more physical blocks. The processor sends multiple write data requests to the solid state disk. Each write data request includes data, and each write data request instructs the solid state disk to write the data into the logical block indicated by the indication information of the logical block. A total size of data included in the multiple write data requests is equivalent to the size of the logical block.