wrong space usied by /opt

deepak_message · 08-14-2012, 01:45 AM

One of redhat server using hide space. unabel to find which space.
/opt has 10gb space, it has using only 500mb. when I do run df -h, it shows 90% use.
please help to find out.

jschiwal · 08-14-2012, 02:05 AM

Quote:

Originally Posted by deepak_message

One of redhat server using hide space.

I don't understand what you mean by this.

Did you use `du -s /opt' to get the 500 MB number?

Is /opt on it's own partition. df will report on the free space and usage of the entire filesystem, not just of a directory.
Another possibility is a sparse file which uses less actual physical space then its size indicates.

A deleted file can still be open by a process, resulting in less free space available. This will be found in /var/run/, /var/tmp/ and /tmp/. Processes do this to prevent accidental temporary file name collisions, and to delete the file automatically if the process crashes. But du won't count it because it isn't in the directory listing.

deepak_message · 08-14-2012, 02:56 AM

yes, when I do du -s /opt' it shows one file whose size is 500MB. nothing else.
but when dun df -h, showing used 90% used /opt.

eSelix · 08-14-2012, 04:58 AM

Can you paste output of these commands (du and df) here. And "ls -la /opt".

Wim Sturkenboom · 08-14-2012, 05:20 AM

Processes can keep files open although they are no longer on the system (e.g. deleted). df will include the size of those files while du does not see them.
The easiest is to reboot the system as that will clear it. The alternative is to use lsof and see which processes have files open and restart those processes.

Code:

lsof |grep deleted

Wim Sturkenboom · 08-14-2012, 05:48 AM

Code:

wim@webserver:~$ df -k
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/cciss/c0d0p4     29577108   3773700  24300948  14% /
/dev/cciss/c0d0p1       489942     27225    437422   6% /boot
/dev/cciss/c0d0p3      3939548    133028   3606396   4% /var
/dev/cciss/c0d1p1    282236376  32795092 235104480  13% /home
wim@webserver:~$ du -k --max-depth 1
170304  ./databases
52      ./forums
31108720        ./backup
20      ./.ssh
540     ./vsftpd-upgrade
1076    ./jannie_assetregister
1101660 ./websites
32382612        .

After opening a file with vim, a temporary file is created by vim

Code:

wim@webserver:~$ df -k
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/cciss/c0d0p4     29577108   3773700  24300948  14% /
/dev/cciss/c0d0p1       489942     27225    437422   6% /boot
/dev/cciss/c0d0p3      3939548    133028   3606396   4% /var
/dev/cciss/c0d1p1    282236376  32795096 235104476  13% /home
wim@webserver:~$ du -k --max-depth 1
170304  ./databases
52      ./forums
31108720        ./backup
20      ./.ssh
540     ./vsftpd-upgrade
1076    ./jannie_assetregister
1101660 ./websites
32382628        .

After deleting the temporary file

Code:

wim@webserver:~$ df -k
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/cciss/c0d0p4     29577108   3773700  24300948  14% /
/dev/cciss/c0d0p1       489942     27225    437422   6% /boot
/dev/cciss/c0d0p3      3939548    133032   3606392   4% /var
/dev/cciss/c0d1p1    282236376  32795108 235104464  13% /home
wim@webserver:~$ du -k --max-depth 1
170304  ./databases
52      ./forums
31108720        ./backup
20      ./.ssh
540     ./vsftpd-upgrade
1076    ./jannie_assetregister
1101660 ./websites
32382612        .
wim@webserver:~$ lsof |grep deleted
vim       16744        wim    4u      REG 104,17   16384 12304625 /home/wim/.goodthingaboutwindows.jpg.swp (deleted)

And after quitting vim, everything is normal again.

jschiwal · 08-16-2012, 01:42 AM

You haven't indicated if /opt is a mount point for a partition or if it is a directory on the root file system. If it is a directory, then df is reporting on the disk usage of /.