[root@host]# df -hdf: cannot read table of mounted file systems[root@host]# cat etc/mtab(nothing)[root@host]# lvdisplayParse error at byte 6 (line 1): unexpected tokenThis is often related to a disk space issue. A post from insanelabs.com recommended freeing up space and then rebuilding /etc/mtab from /proc/mounts like so:[root@host]# grep -v rootfs /proc/mounts > /etc/mtab..