Disclosed herein is a method of managing data in an asymmetric cluster file system. In this method, if an OPEN request for the opening of an absent file has been received, a metadata server assigns a file handle value and a file name and then generates a file in a data server. Thereafter, the metadata server copies a file stored in the data server or the generated file to one or more data servers based on a preset copying level. Thereafter, a client performs a file operation on the files stored in the data servers.