MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
          Given a byte count, converts it to human-readable format and
          returns a string consisting of a value and a units indicator.
          Depending on the size of the value, the units part is
          bytes, KiB (kibibytes),
          MiB (mebibytes), GiB
          (gibibytes), TiB (tebibytes), or
          PiB (pebibytes).
        
mysql> SELECT sys.format_bytes(512), sys.format_bytes(18446644073709551615);
+-----------------------+----------------------------------------+
| sys.format_bytes(512) | sys.format_bytes(18446644073709551615) |
+-----------------------+----------------------------------------+
| 512 bytes             | 16383.91 PiB                           |
+-----------------------+----------------------------------------+