On Wed, Nov 21, 2007 at 07:37:31PM -0500, Ugo Bellavance wrote:
2 of my Centos4 servers are showing weird behavior.
[root@server1 ~]# du -sh /var/ 1.8G /var/ [root@server1 ~]# df -h /var Filesystem Size Used Avail Use% Mounted on /dev/sda7 4.3G 3.9G 181M 96% /var
There are two things to consider.
ONE ===
If you have large block sizes and lots and lots of small files then "du" will report a number quite a lot smaller than "df". "df" reports on actually amount free; "du" reports on apparent size of the files used.
TWO ===
If you delete a file that is still "open" (typically a log file, or a file being written to in /var/tmp) then Unix doesn't actually delete the file at that point; it removes the directory entry and marks the file to be deleted when no one is using it any more.
I've seen developers create debug logs in /tmp that grew to 2Gb then delete them to save space... while the program was still writing more debug messages, so they didn't save any space at all.