confusion about disk space - where's my 5GB?

[yyghp]

I noticed there were a same disk space issue on three of our oracle 10g servers, running Red Hat Enterprise Linux 3.
When I use "df -h", I could see:
# df -h
Filesystem Size Used Avail Use% Mounted on
...
/dev/vg00/lv06 9.7G 8.2G 1.1G 90% /u01

Which showed /u01 had used 8.2GB.

While I checked with "du -ks":
# du -ks /u01
3139912 /u01
# du -hs /u01
2.9G /u01

( /u01 is an Oracle directory )
# du -hs /u01/app/oracle
2.9G /u01/app/oracle


It showed only 3GB!
Why? Where's the other 5GB?
Thanks!

[Alpha977]

Hello!

have you checked with

"fdisk -l" ?
Is this disk "mounted"?

[yyghp]

Yeah, /u01 is mounted, that's why I can see the content under.
Thanks!

[Heironimus · Accepted solution]

Usually a discrepancy between df and du is caused by some files having been deleted while a process is still holding them open. Until the process either exits or explicitly closes the file the space won't be freed, but the links in the filesystem are gone so you can't see or measure it.

lsof might help find open-but-unlinked files.

[Steven E. Protter]

Shalom,

Generally when this happens there is a process with a file handle on a file you deleted as sysadmin.

Kill the process and the space is recognized.

The different utils have been known to give inconsistent answers and normally a system boot clears this up.

SEP

[yyghp]

Thanks!
Yes, the space was released after restart the oracle services.
Points added!