Mounting A partition in Linux
Once you insert new hard disks into your system,
you’ll typically use utilities like fdisk or parted to create partitions. Once
you create a partition, you’ll use mkfs command to create or format ext2, ext3, or ext4 partition.
Once you create a partition, you should use mount
command to mount the partition into a mount point (a directory), to start using
the filesystem.
About
mount and umount
The mount command mounts a storage device or
filesystem, making it accessible and attaching a directory to the file system.
The umount command "unmounts" a mounted
filesystem, informing the system to complete any pending read or write
operations, and safely detaching it.
There
are two types of mounting which will be used in LINUX or any UNIX. These are
fallows.
- Temporary Mounting
- Permanent Mounting
Temporary
Mounting
In a temporary mount point we will create a
directory and mount it but this mount point will lasr only till the system is
up, once it is rebooted the mounting will be lost.
Syntax:
#mount
<device name> <directory name (Mount Point)>
#mount
/dev/sda8 /dir1
[root@rahul
~]# mount /dev/sda8 /dir1
[root@rahul
~]#
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To
view all the mounted partitions
After you execute mount a partition or
filesystem, execute the mount command without any arguments to view all the
mounts.
#mount
[root@rahul
~]# mount
/dev/sda2
on / type ext4 (rw)
oproc
on /proc type proc (rw)
sysfs
on /sys type sysfs (rw)
devpts
on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs
on /dev/shm type tmpfs
(rw,rootcontext="system_u:object_r:tmpfs_t:s0")
/dev/sda1
on /boot type ext4 (rw)
none
on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc
on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
gvfs-fuse-daemon
on /root/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev)
/dev/sr0
on /media/RHEL_6.0 x86_64 Disc 1 type iso9660
(ro,nosuid,nodev,uhelper=udisks,uid=0,gid=0,iocharset=utf8,mode=0400,dmode=0500)
[root@rahul
~]#
|
Now we have successfully mounted the partition we
can access it and can store the data
To add the data access the mount point
- #cd /dir1
Add the data and exit the directory
How
to Unmounting a Partition
#
umount <mount point directory>
# umount
/kernel
[root@rahul
~]# umount /dir1
|
Now verify it with mount command
[root@rahul
~]# mount
/dev/sda2
on / type ext4 (rw)
oproc
on /proc type proc (rw)
sysfs
on /sys type sysfs (rw)
devpts
on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs
on /dev/shm type tmpfs
(rw,rootcontext="system_u:object_r:tmpfs_t:s0")
/dev/sda1
on /boot type ext4 (rw)
none
on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc
on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
gvfs-fuse-daemon
on /root/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev)
/dev/sr0
on /media/RHEL_6.0 x86_64 Disc 1 type iso9660
(ro,nosuid,nodev,uhelper=udisks,uid=0,gid=0,iocharset=utf8,mode=0400,dmode=0500)
[root@rahul
~]#
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Permanent
Mounting
Permanent mounting procedure is exactly same like
temp mounting, but here we will update the /etc/fstab
file with the mounting details, so that it will be mounted even after the
system is reboot.
Steps To Make a permanent mount point:
- Make a directory or use an existing directory
- Add entry in /etc/fstab file
- Use mount –a command to check it is mounting. (mount –a will mount all the entry placed in /etc/fstab)
Here we will be using our existing /dir1 directory as mount point which is
created previously.
#vim
/etc/fstab
#
#
/etc/fstab
#
Created by anaconda on Sat Aug 13 17:36:51 2016
#
#
Accessible filesystems, by reference, are maintained under '/dev/disk'
#
See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
UUID=4afa457a-d662-4e89-b4e2-09303c44c3eb
/ ext4 defaults 1 1
UUID=752c2f33-fe60-4269-9480-b27260fc3777
/boot ext4 defaults
1 2
UUID=496b4058-1c64-47e0-97f8-8760f41aaef8
swap swap defaults 0 0
tmpfs /dev/shm tmpfs defaults 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
oproc /proc proc defaults 0 0
/dev/sda5 swap swap defaults 0 0
/dev/sda8 /dir1 ext4 defaults 0 0
~
~
Device
name
Mount point Type of fs Mount options
Dumping Check sequence
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The filesystems listed in /etc/fstab gets mounted
during booting process. After booting, system administrator may unmount some of
the partitions for various reasons. If you want all the filesystems to be
mounted as specified in /etc/fstab, use -a option with mount as shown below:
#mount
–a
[root@rahul
~]# mount -a
[root@rahul
~]# mount
/dev/sda2
on / type ext4 (rw)
oproc
on /proc type proc (rw)
sysfs
on /sys type sysfs (rw)
devpts
on /dev/pts type devpts (rw,gid=5,mode=620)
tmpfs
on /dev/shm type tmpfs
(rw,rootcontext="system_u:object_r:tmpfs_t:s0")
/dev/sda1
on /boot type ext4 (rw)
none
on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
sunrpc
on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
gvfs-fuse-daemon
on /root/.gvfs type fuse.gvfs-fuse-daemon (rw,nosuid,nodev)
/dev/sr0
on /media/RHEL_6.0 x86_64 Disc 1 type iso9660
(ro,nosuid,nodev,uhelper=udisks,uid=0,gid=0,iocharset=utf8,mode=0400,dmode=0500)
/dev/sda8
on /dir1 type ext4 (rw,acl)
[root@rahul
~]#
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You can now access the directory and add, delete or
modify the contents and can also unmount the file system at any point.
- How we can check all mounted partitions of specific type
It is possible to list only the specific type of
filesystem mounted using the option -l with -t as shown below:
#
mount -l -t ext2
/dev/sda6 on /mydata type ext2 (rw)
#
mount -l -t ext4
/dev/sda5 on / type ext4 (rw,errors=remount-ro)
As seen above, /dev/sda6 is the only ext2 partition
and /dev/sda5 is the only ext4 partition accordingly.
- How to Mount a Floppy Disk in linux
The device file for floppy disk would exist under
/dev directory. For example, a floppy disk will be mounted as shown below.
#
mount /dev/fd0 /mnt
#
cd /mnt
After the successful mount, you would be able to
access the contents of the floppy disk. Once you are done with it, use umount
before you physically remove the floppy disk from the system.
#
umount /mnt
- How we can Mount filesystem with read or read/write access
To mount partition as read only, use -r option which
is synonym to -o ro.
#
mount /dev/sda6 /mydata -r
#
mount | grep /mydata
/dev/sda6 on /mydata type ext4 (ro)
ext3 and ext4 filesystem would still allow you to do
write operation when the filesystem is dirty. So, you may have to use
“ro,noload” to prevent these kind of write operation.
#
mount /dev/sda6 /mydata -t ext4 -o ro -o noload
#
mount | grep /mydata
/dev/sda6 on /mydata type ext4 (ro,noload)
To mount a partition with read/write access, use -w
option which is same as “-o rw” (i.e : default).
- How to Remount the mounted filesystem in linux
In order to mount the already mounted filesystem,
use remount option and its normally used to remount the filesystem with
read/write access when its previously mounted with read access.
The /mydata mount point is going to be remounted
with read/write access from read access as shown below:
#
mount | grep /mydata
/dev/sda6 on /mydata type ext4 (ro,noload)
#
mount -o remount,rw /mydata
#
mount | grep /mydata
/dev/sda6 on /mydata type ext4 (rw)
- How to Mount an iso image into a directory
The iso image can be mounted as shown below:
#
mount -t iso9660 -o loop notes_collections.iso /mnt
#
cd /mnt
#
ls
sql/
java/ .net/
- How to Unmount more than one mount points
Umount allows you to unmount more than mount point
in a single execution of umount of command as follows:
#
umount /mydata /backup
#
mount | grep /mydata
#
mount | grep /backup
- How can i Forcefully unmount a filesystem
umount provides the option to forcefully unmount a
filesystem with option -f when the device is busy as shown below:
#
umount -f /mnt
If this doesn’t work for you, then you can go for
lazy unmount.
Meanwhile, you can also have a look at ps command output
that which process is presently using the mountpoint as shown below:
#
ps ajx | grep /mydata
2540 3037
3037 2468 pts/2 3037 D+ 0
0:00 cp -r /home/geekstuff/ProjectData/ /mydata
You can also execute fuser command to find out which
process is holding the directory for operations.
#
fuser -cu /mydata
/mydata:
3087(root)
It gives you the process id with username (nothing
but the owner of the process). If you know what that process is, you may want
to stop that process and then try the umount again.
- How to assign a label to the partition?
Assigning the label means giving some name to
partition. For assigning label to partition e2label command is used.
Syntax:
#e2label
<partition name> <label>
Ex:
#e2label
/dev/sda7 mountdisk
To check the assigned label
#e2label
/dev/sda7
[root@rahul
~]# e2label /dev/sda8 rahul
[root@rahul
~]# e2label /dev/sda8
rahul
[root@rahul
~]#
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To list all the mounted partition along with their
labels, use mount –l command
- How to mount a partition using its label?
Mounting a /dev/sda8 partition with its label rahul,
verify it with mount command
[root@rahul
~]# mount LABEL=rahul /dir1
[root@rahul
~]# mount
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Make
a permanent mount point using label
As we know that to make a permanent mounting, as entry
has to be made in /etc/fstab file.
#
vim /etc/fstab
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
oproc /proc proc defaults 0 0
/dev/sda5 swap swap defaults 0 0
LABEL=rahul /dir1 ext4 defaults 0 0
|
Now use mount
–a command and verify it with mount
command whether it is mounted or not.
- How to mount a partition permanently with its block id(UUID) ?
- To check a uuid of a partition use blkid /dev/sda8 command.
- Copy the uuid.
- Make an entry in /etc/fstab using UUID
- Verify it with mount –a option
[root@rahul
~]# blkid /dev/sda8
/dev/sda8:
LABEL="rahul" UUID="2a5fb5c4-9500-414b-9598-fb82a470cc90"
TYPE="ext4"
[root@rahul
~]#
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#
vim /etc/fstab
devpts /dev/pts devpts gid=5,mode=620 0 0
sysfs /sys sysfs defaults 0 0
oproc /proc proc defaults 0 0
/dev/sda5 swap swap defaults 0 0
UUID="2a5fb5c4-9500-414b-9598-fb82a470cc90" /dir1
ext4
defaults 0 0
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Now mount it with mount –a command and verify it with mount command.
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