Linux directory size(including sub directory)

du -hs <directory>

-h, --human-readable  print sizes in human readable format (e.g., 1K 234M 2G)
-s, --summarize       display only a total for each argument

skysign@skysign-dt:~$ du -hs ./mirror/ 287G    ./mirror/ skysign@skysign-dt:~$