Storage space saving method and system

The invention discloses a storage space saving method. The storage space saving method comprises the following steps: setting a storage area of back-end storage into a compressed storage area and a non-compressed storage area; writing user data into a back-end storage, analyzing the popularity of the user data, and selecting a storage area of the user data; updating the user data popularity according to a preset period, and transferring the storage area of the user data according to the user data popularity. The invention further discloses a storage space saving system. Two storage areas are arranged, hot spot data frequently accessed by a user is stored in a non-compression storage area, and the access speed of the data is not influenced.Cold data which are not frequently used by users are stored in the compression storage area, and the purpose of saving space is achieved. The sizes of the non-compression storage area and the compression storage area can be dynamically adjusted, the optimal points of the sto