df command show no output

Question

I'm running the linux distro on my server.When i want to verify the size of the disk, i'm issuing this commnand to get the output.

 df -h

But it does not produce ANY output.Strangely enough when i'm issuing other command such as fdisk -l or du -h it can show output normally.

Does anyone now why is this happening?Thanks.

edit:

here is the output of cat /etc/fstab

 none     /dev/pts       devpts   rw   0     0

and this is for mount command

 none on /dev/pts type devpts (rw)
 none on /proc/sys/fs/binfmt_misc tpe binfmt_misc  (rw)

edit(2):

here is the output of cat /proc/mounts

 /dev/vzfs / vzfs rw,relatime,usrquota,grpquota 0 0
 proc /proc proc rw,relatime 0 0
 sysfs /sys sysfs rw,relatime 0 0
 none /dev/tmpfs rw,relatime 0 0
 none /dev/pts devpts rw,relatime 0 0
 none /proc/sys/fs/binfmt_misc binfmt_msc rw,relatime 0 0

Answer 1

How about this:

$ \df

\ to ignore df alias.

---

UPDATE

here is the output of cat /proc/mounts

 /dev/vzfs / vzfs rw,relatime,usrquota,grpquota 0 0

/dev/vzfs --> looks like you're running OpenVZ (check by using virt-what). And if so, root filesystem is mounted by the host system, not the guest, therefore, there is no / in the /etc/mtab and df shows nothing. To fix, link /etc/mtab to /proc/mounts:

rm -f /etc/mtab
ln -s /proc/mounts /etc/mtab

Source: http://wiki.openvz.org/Gentoo_template_creation#Make_.2Fetc.2Fmtab_a_symlink_to_.2Fproc.2Fmounts

Answer 2

It may be that you are not running the correct df; perhaps there is a badly-named alias or shellscript in your path. Run which df to check.

If you are running the correct df, then perhaps it has been corrupted or overwritten. Run rpm -qf $(which df) to see which package owns df, and then run rpm -V packagename or rpm -V $(rpm -qf $(which df)) to see if it has changed since installation.