Storage device including the volatile memory and operating method of storage device

A storage device comprising:

• volatile memory comprising a plurality of physical regions each comprising a plurality of storage space;
• a compression operation unit configured to generate compression data by compressing management request data, among a plurality of write data, wherein a compression size of the compression data is determined based on properties of the management request data;
• and
• a control operation unit configured to:
• divide the plurality of physical regions into first and second physical regions;
• assign, to the second physical regions, a plurality of selection regions based on an N reference storage space size in accordance with each of the plurality of write data;
• set, as a retention region, M regions determined based on a difference between the compression size and the reference storage space size, among the first physical regions, when the compression size is greater than the reference storage space size;
• generate logical information indicative of the retention region;
• store multiple data items of the compression data and the logical information in a request selection region corresponding to the management request data, among the plurality of selection regions;
• and
• store remaining data items of the compression data in the retention region.