LPIC-1 Exam Objective 104.3: Control Mounting and Unmounting of Filesystems #
In this tutorial, we’ll cover how to control the mounting and unmounting of filesystems on Linux systems. We’ll explore commands and configurations for both Ubuntu/Debian and Enterprise Linux (such as RHEL/CentOS) distributions, noting any differences between them.
Key Knowledge Areas #
- Manually mount and unmount filesystems.
- Configure filesystem mounting on bootup.
- Configure user-mountable removable filesystems.
- Use of labels and UUIDs for identifying and mounting filesystems.
- Awareness of systemd mount units.
Tools and Files #
/etc/fstab
/media/
mount
umount
blkid
lsblk
1. Manually Mount and Unmount Filesystems #
Mounting a Filesystem #
The mount
command is used to attach a filesystem to the filesystem hierarchy at a given mount point.
Example:
sudo mount /dev/sda1 /mnt
This mounts the device /dev/sda1
to the directory /mnt
.
Unmounting a Filesystem #
The umount
command is used to detach a filesystem from the filesystem hierarchy.
Example:
sudo umount /mnt
This unmounts the filesystem mounted at /mnt
.
2. Configure Filesystem Mounting on Bootup #
The /etc/fstab
file contains information about filesystems and where they should be mounted. Entries in this file will be mounted at boot time.
Example /etc/fstab
entry:
/dev/sda1 /mnt ext4 defaults 0 2
This line configures /dev/sda1
to be mounted at /mnt
using the ext4
filesystem with default options.
3. Configure User-Mountable Removable Filesystems #
To allow users to mount removable filesystems, entries can be added to /etc/fstab
with the user
option.
Example /etc/fstab
entry:
/dev/sdb1 /media/usb vfat noauto,user 0 0
This line allows any user to mount the /dev/sdb1
device to /media/usb
using the vfat
filesystem.
4. Use of Labels and UUIDs for Identifying and Mounting Filesystems #
Using labels and UUIDs can be more reliable than device names, which can change between boots.
Finding UUIDs and Labels #
The blkid
command can be used to display UUIDs and labels of devices.
Example:
sudo blkid /dev/sda1
Output:
/dev/sda1: UUID="e2e2e2e2-2e2e-2e2e-2e2e-2e2e2e2e2e2e" TYPE="ext4" LABEL="mydisk"
Using UUIDs and Labels in /etc/fstab
#
Example using UUID:
UUID=e2e2e2e2-2e2e-2e2e-2e2e-2e2e2e2e2e2e /mnt ext4 defaults 0 2
Example using Label:
LABEL=mydisk /mnt ext4 defaults 0 2
5. Awareness of systemd Mount Units #
Systemd uses mount units to manage mount points. These units are automatically created from /etc/fstab
entries, but they can also be manually created.
Example of a Manual Mount Unit #
Create a file named /etc/systemd/system/mnt-data.mount
with the following content:
[Unit]
Description=Mount data
[Mount]
What=/dev/sda1
Where=/mnt/data
Type=ext4
[Install]
WantedBy=multi-user.target
Reload the systemd manager configuration and start the mount unit:
sudo systemctl daemon-reload
sudo systemctl start mnt-data.mount
sudo systemctl enable mnt-data.mount
Commands and Utilities #
mount
#
Used to mount filesystems.
Syntax:
mount [options] <device> <mount-point>
umount
#
Used to unmount filesystems.
Syntax:
umount [options] <mount-point|device>
blkid
#
Used to locate/print block device attributes.
Syntax:
blkid [options] <device>
lsblk
#
Used to list information about block devices.
Syntax:
lsblk [options] [device]
Conclusion #
This tutorial has covered the essentials for controlling the mounting and unmounting of filesystems in Linux, including practical examples and configurations for both Ubuntu/Debian and Enterprise Linux systems. Understanding these concepts and commands is crucial for effectively managing Linux filesystems, especially for the LPIC-1 certification exam.