The present invention provides a sever which includes a network interface, a processor and a first storage device, wherein the processor is arranged for communicating with an electronic device via the network interface, and the first storage device stores data. In the operations of the server, the processor determines whether the data is cold data; and when the data is determined as the cold data, the processor moves a second portion of the data to a second storage device, and a first portion of the data is remained in the first storage device, wherein the data amount of the first portion is less than data amount of the second portion, and the access speed of the first storage device is higher than the access speed of the second storage device.