Storage system and method for controlling storage system

A method for controlling a storage system including a plurality of control devices, the plurality of control devices each including a storage unit, a saving unit, an interface unit, and an arithmetic processing unit, the method comprising:

• receiving, by a first interface unit, an instruction regarding output or input of data to or from a storage device, the first interface unit being included in a first control device out of the plurality of control devices;
• receiving, by a first arithmetic processing unit, the instruction from the first interface unit and executing the instruction, the first arithmetic processing unit being included in the first control device;
• storing by the first arithmetic processing unit, when requested to execute saving processing for saving dump data of a second interface unit in which an error has occurred, the dump data collected from the second interface unit into the storage unit, the second interface unit being included in a second control device out of the plurality of control devices;
• calculating, by the first arithmetic processing unit, an execution time of the saving processing;
• compressing by the first arithmetic processing unit, when the execution time exceeds a time limit and before a remaining time is reached, part of the dump data stored in the storage unit and saving the compressed dump data into the saving unit;
• and
• saving by the first arithmetic processing unit, when the execution time exceeds the time limit and after the remaining time has been reached, rest of the dump data stored in the storage unit into the saving unit without compression.