A storage device includes: a nonvolatile memory including power loss protector (PLP) memory blocks configured to store at least one of meta data or user data for data backup; a buffer memory configured to store at least one of the meta data or the user data stored in the PLP memory blocks; a charging circuit configured to generate electric power for data backup in response to a sudden power off (SPO) occurrence, and transmit a first charging complete signal or a second charging complete signal to a processor according to a level of the electric power, and; and the processor configured to control at least one of the nonvolatile memory and the buffer memory to execute a first request from a host related to the meta data with priority in response to the first charging complete signal, and execute a second request from the host related to the meta data or the user data in response to the second charging complete signal.