Patent ID: 8700684

Claim:
A file management apparatus for managing a file in a distributed storage system in which one file is stored in a plurality of storage devices in a distributed manner, the apparatus comprising: a storage device; an inquiry frequency counting unit for counting the number of inquiries on a file requested by a client; a hot file selection unit for determining whether or not to select the file as a hot file based on the number of inquiries counted on the file; and a hot file management unit for managing the file selected as a hot file to be separated from files that are not selected as a hot file, wherein the hot file selection unit selects the file as a hot file if the number of inquiries counted in a certain counting period is larger than a hot file selection threshold value, wherein the inquiry frequency counting unit counts the number of inquiries on the file by subtracting the number of inquiries corresponding to an oldest session from the number of inquiries counted in a previous counting period and then adding the number of inquiries counted in a new session, and wherein a length of the oldest session is a value obtained by dividing the previous counting period by an exponentiation of two.