A question about checking HD

thomas2004ch · 11-26-2009, 12:56 AM

I use 'df -h' and get:

Code:

[root@s003ap02-test ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/mapper/vg_root-lv_root
                      3.0G  2.3G  551M  81% /
/dev/sda1              99M   15M   80M  16% /boot
none                  3.0G     0  3.0G   0% /dev/shm
/dev/mapper/vg_root-lv_home
                      496M  153M  318M  33% /home
/dev/mapper/vg_root-lv_opt
                      7.9G  3.3G  4.3G  43% /opt
/dev/mapper/vg_root-lv_tmp
                      496M   83M  389M  18% /tmp
/dev/mapper/vg_root-lv_var
                      2.0G  462M  1.5G  25% /var

It seems the volume root used 2.3 GB. But as I use 'du -shc /*' to check I get:

Code:

[root@s003ap02-test ~]# du -shc /*
6.1M    /bin
14M     /boot
4.0K    /cjtemp
236K    /dev
14M     /etc
143M    /home
8.0K    /initrd
102M    /lib
17M     /lib64
28K     /logs
16K     /lost+found
16K     /media
12K     /mnt
3.2G    /opt
7.3G    /proc
209M    /root
18M     /sbin
8.0K    /selinux
8.0K    /srv
0       /sys
72M     /tmp
1.4G    /usr
411M    /var
13G     total

Here one can see the /root just used 209 M.

Why?

Unknown_User · 11-26-2009, 01:14 AM

You are not comparing like-for-like so they won't be the same - The second output shows details of your local filesystem but the first relates to mapped directories.

Despite having similarities such as the 'root' title they are logically (and possibly physically) seperate.

shpenat · 11-26-2009, 01:54 AM

df will indicate usage on each partition mounted in your system. One partition have to be mounted as / and is often called "root".

du on the other hand will indicate haw much space each file or directory uses. On / partition is usually folder called /root which is "home" for root user (but it can have its separate partition).

So if you want the results to match each other you would have to add all folders on one partition together (i.e. to get your / size you will have to add size of all folder listed in du output except /boot /home /opt /tmp and /var which are on separate partitions)