Datafile Size

Kindly clarify my doubt on datafile size. I have noticed that the datafile size is different from OS level vs database. When I query to get the size of SYSAUX tablespace on database it showed me 310 MB, But on OS it showed me 830M.

SQL> select file_name,tablespace_name,bytes/1024/1024, maxbytes/1024/1024,AUTOEXTENSIBLE

  2 from dba_data_files where tablespace_name='SYSAUX' order by file_name;

FILE_NAME

TABLESPACE_NAME                BYTES/1024/1024 MAXBYTES/1024/1024 AUT

------------------------------ --------------- ------------------ ---

/DATA/ORACLE/datafiles/sysaux01.dbf

SYSAUX                                     310                  0 NO

bash-3.00$ pwd

/DATA/ORACLE/datafiles/

bash-3.00$ du -sh sysaux01.dbf

 830M sysaux01.dbf

bash-3.00$

How this is possible?

Regards,
Naga

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