A computer-implemented method for data mirroring for network attached storage includes duplicating an identity mapping database on a second NAS server and creating a queue of updated data files containing updated elements since a prior synchronization. Data files containing the updated elements are transmitted from the first NAS server to the second NAS server. An updated copy of the identity mapping database from the first NAS server is stored at the second NAS server. The updated data files and metadata information from the first NAS server are written to the second NAS server. The permission entries of the transmitted data files from the first NAS server are translated using the identity mapping databases of the first and second NAS servers, such that the permission entries reflect the local ID mapping database on the second NAS server.