$ set security /class=file -
    /acl=(identifier=[*,*], option=default, access=none) dkb200:[000000]mega_rdb.dir
$ set security/class=file -
    /acl=(identifier=mega_ro, option=default, access=read) dkb200:[000000]mega_rdb.dir
$ set security/class=file -
    /acl=(identifier=mega_rw, option=default, access=read+write+execute) dkb200:[000000]mega_rdb.dir
$ set security/class=file -
   /acl=(identifier=mega_dba, option=default, access=read+write+execute+delete) dkb200:[000000]mega_rdb.dir