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Old 06-18-2010, 12:27 PM   #1
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Why filesystem cannot unmount when it clearly show that it has been mounted?

Linux Distribution Centos 5.3
here's my release.
[root@localhost ~]# uname -r
[root@localhost ~]# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda7              12G  3.8G  7.2G  35% /
/dev/sda11            9.7G  151M  9.0G   2% /backup
/dev/sda9             8.6G  177M  7.9G   3% /u02
/dev/sda8             5.2G  173M  4.7G   4% /u01
/dev/sda10             13G  292M   12G   3% /home
/dev/sda12             39G   33G  4.3G  89% /vmware
/dev/sda6              99M   17M   78M  18% /boot
tmpfs                 1.8G     0  1.8G   0% /dev/shm
/dev/sda2              35G   17G   18G  48% /mymnt/win
/dev/sda3              74G   55G   19G  75% /mymnt/e_partition
here's my /etc/fstab
LABEL=centos_root       /                       ext3    defaults        1 1
LABEL=oracle_recovery   /backup                 ext3    defaults        1 6
LABEL=oracle_data       /u02                    ext3    defaults        1 5
LABEL=oracle_software_  /u01                    ext3    defaults        1 4
LABEL=shared_home       /home                   ext3    defaults        1 3
LABEL=vmware_partition  /vmware                 ext3    defaults        1 7
LABEL=boot              /boot                   ext3    defaults        1 2
tmpfs                   /dev/shm                tmpfs   defaults        0 0
devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
sysfs                   /sys                    sysfs   defaults        0 0
proc                    /proc                   proc    defaults        0 0
LABEL=swap              swap                    swap    defaults        0 0
/dev/sda2       /mymnt/win   ntfs-3g  ro,umask=0222,defaults 0 0
/dev/sda3       /mymnt/e_partition   ntfs-3g  rw,umask=0000,defaults 0 0
df -h will state what are the filesystems that are mounted. but how come when I try to umount /dev/sda11, it state that it did not mount, any reason for the misleading information?
[root@localhost ~]# umount /dev/sda11 /backup
umount: /dev/sda11: not mounted
umount: /dev/sda11: not mounted
[root@localhost ~]#
Old 06-18-2010, 12:45 PM   #2
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/dev/sda11 is not mounted

/backup is mounted.

You umount the mount point not the device.

man umount
The umount command detaches the file system(s) mentioned from the file hierarchy. A file system is specified by giving the directory where it has been mounted. Giving the special device on which the file system lives may also work, but is obsolete, mainly because it will fail in case this device was mounted on more than one directory.

Last edited by smoker; 06-18-2010 at 12:47 PM.
Old 06-18-2010, 12:46 PM   #3
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Try to omit "/backup" in
umount /dev/sda11 /backup
to see if the same error reports
Old 06-18-2010, 09:21 PM   #4
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Originally Posted by smoker View Post
/dev/sda11 is not mounted

/backup is mounted.

You umount the mount point not the device.

man umount
Actually it works ether way.
Further, I, myself have had this problem also but I just rebooted to fix it (which isn't always desirable).


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