A data processing method and apparatus, a server, and a controller, where the method includes receiving, by a server, a data processing request, where the data processing request includes a request sequence number, and the request sequence number marks the data processing request, generating at least one input/output (I/O) request according to the data processing request, adding the request sequence number to each of the at least one I/O request, merging the I/O requests having the request sequence number, and generating an aggregation instruction when a quantity of I/O requests having the request sequence number is greater than a preset threshold, and sending the aggregation instruction to a controller of a storage system. Hence, a time taken to perform monitoring and management using a transaction mechanism can be reduced, thereby simplifying the transaction mechanism.