What OS are you working on?? I'm currently working with an HP-UX server & the data file size is only off by 8K which I do believe is the header block for the file & would not be reported as usable. Dick Goulet ________________________________ From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Nagaraj S Sent: Monday, February 09, 2009 1:59 PM To: oracle-l@xxxxxxxxxxxxx Subject: Re: Datafile Size Also du -sh and ls -ltrh shows different output. bash-3.00$ ls -ltrh -rw-rw---- 1 oracle dba 1.5G Feb 9 08:09 sysaux01.dbf bash-3.00$ du -sh sysaux01.dbf 830M sysaux01.dbf SQL> select sum(space_usage_kbytes) from v$sysaux_occupants; 309504 On Mon, Feb 9, 2009 at 10:59 PM, Nagaraj S <nagaraj.chk@xxxxxxxxx> wrote: Hi Gurus, Kindly clarify my doubt on datafile size. I have noticed that the datafile size is different from OS level vs database. When I query to get the size of SYSAUX tablespace on database it showed me 310 MB, But on OS it showed me 830M. SQL> select file_name,tablespace_name,bytes/1024/1024, maxbytes/1024/1024,AUTOEXTENSIBLE 2 from dba_data_files where tablespace_name='SYSAUX' order by file_name; FILE_NAME ------------------------------------------------------------------------ -------- TABLESPACE_NAME BYTES/1024/1024 MAXBYTES/1024/1024 AUT ------------------------------ --------------- ------------------ --- /DATA/ORACLE/datafiles/sysaux01.dbf SYSAUX 310 0 NO bash-3.00$ pwd /DATA/ORACLE/datafiles/ bash-3.00$ du -sh sysaux01.dbf 830M sysaux01.dbf bash-3.00$ How this is possible? Regards, Naga