The present disclosure relates to a storage device that optimally maintains a size of debugging data. Disclosed is a memory controller, including a first interface may communicate with a first external device; a second interface may generate a signal for controlling an operation of a second external device; a first volatile memory buffer; and a processor may generate and store the telemetry log data in the first volatile memory buffer; move and store the telemetry log data stored in the first volatile memory buffer to a first non-volatile memory buffer, when a size of the telemetry log data stored in the first volatile memory buffer is greater than or equal to a threshold size; and set the threshold size based on at least one among a number of telemetry logs stored in the first volatile memory buffer and a rising momentum of the number of the telemetry logs.