Linux Tactic

Mastering Logical Volume Management: A Comprehensive Guide

Introduction to LVM and Pre-Requisites

Have you ever run out of space on your hard drive and wished that you could just magically increase its size? Well, with Logical Volume Management (LVM), you can! LVM is a flexible system that allows you to increase the size of a logical volume by adding physical volumes to it.

In this article, we will explore the methods for increasing logical volume size using LVM, as well as the pre-requisites necessary to follow this tutorial.

Pre-Requisites for Following the Tutorial

Before we dive into LVM, let’s make sure we have all the necessary pre-requisites. To use LVM, you must have at least one physical device, a volume group, and a logical volume.

A physical device is any storage device that is connected to your system, such as a hard drive or a solid-state drive. You will need to have at least one of these devices to create a physical volume.

A volume group is a collection of physical volumes that work together to provide logical volume storage. You will need to create a volume group before creating a logical volume.

A logical volume is a virtual partition that is created from a pool of storage. You can create multiple logical volumes within a volume group, each with its own size and properties.

Creating a New Physical Volume

Now that we have all the pre-requisites in place, let’s start creating a new physical volume.

Listing Available Physical Devices Connected to the System

First, we need to find out which physical devices are connected to our system. We can do this by using the “lsblk” command.

This command lists all available block devices, including hard drives, USB drives, and CD-ROMs.

Attaching a new Physical Device and Listing all Connected Devices

If you are adding a new physical device, you will need to attach it to your system before you can use it. Once the device is attached, use the “lsblk” command again to verify that the new device is listed.

Formatting the Device and Creating a Physical Volume using pvcreate Command

Next, we need to format the device and create a physical volume using the “pvcreate” command. This command creates a new physical volume on the specified device.

You can also specify the size of the physical volume, although this is optional.

Displaying all Physical Volumes

Finally, we can view all physical volumes on our system using the “pvs,” “pvscan,” or “pvdisplay” commands. These commands display information about each physical volume, such as its size, free space, and UUID (Unique Universal Identifier).

This information is helpful when working with LVM, as it allows you to identify which physical volumes are available for use.

Conclusion

Logical Volume Management allows you to be more flexible with your storage and increase the size of your logical volumes using physical volumes. By following these simple steps, you can create new physical volumes and view all physical volumes connected to your system.

With LVM, you no longer have to worry about running out of space on your hard drive!

Extending the Volume Group

Now that we have created a physical volume and verified its existence, let’s move on to extending the volume group. A volume group is an important concept in LVM because it acts as a container for one or more physical volumes.

To extend a volume group, we will use the “vgextend” command. The syntax for this command is as follows:

“`

vgextend [Volume Group Name] [Physical Volume Name]

“`

For example, if our volume group is named “VG1” and our physical volume is “sdb1”, we would enter the following command:

“`

sudo vgextend VG1 /dev/sdb1

“`

This command will add the “sdb1” physical volume to the “VG1” volume group.

Listing Volume Group Details

Once the volume group has been extended, we can view its details using the “vgdisplay” command. This command displays information about the volume group, including its name, size, free space, physical volumes, and more.

For example, to display the details of the “VG1” volume group, we would enter the following command:

“`

sudo vgdisplay VG1

“`

This command will show us all the details of the “VG1” volume group, including the added physical volume.

Extending the Logical Volume

Now that we have extended the volume group, we can move on to extending the logical volume. The logical volume is the second component in the LVM setup and acts as a virtual partition that uses the free space in the volume group.

To extend our logical volume, we will use the “lvextend” command. The syntax for this command is as follows:

“`

lvextend [option(s)] [Logical Volume Path] [Size]

“`

For example, let’s say we have a logical volume named “LV1” in “VG1”, and we want to extend it by another 10GB.

We would enter the following command:

“`

sudo lvextend -L +10G /dev/VG1/LV1

“`

This command will extend the size of “LV1” by 10GB via the “-L” flag and the “+10G” option. Note that the size of the logical volume can be specified in either GB, TB, MB, or sectors.

Listing Existing Logical Volumes

Now that we have extended our logical volume, we can use the “lvdisplay” command to view the details of all logical volumes on the system. This command displays information about the logical volume, such as its name, size, and extents.

For example, to display the details of all logical volumes on the system, we would enter the following command:

“`

sudo lvdisplay

“`

This command will show us all the details of the logical volumes on our system, including the recently extended “LV1”.

Listing Logical Volume Details

Finally, we can use the “lvdisplay” command to view the specifics of a logical volume. This command displays more detailed information about a specific logical volume, such as its UUID, read-only status, and more.

For example, to display the details of “LV1”, we would enter the following command:

“`

sudo lvdisplay /dev/VG1/LV1

“`

This command will show us all the details of the “LV1” logical volume, including its new, extended size.

Conclusion

In conclusion, by extending the volume group and logical volume using the “vgextend” and “lvextend” commands respectively, we were able to increase the storage capacity of our LVM setup. Using the “vgdisplay” and “lvdisplay” commands, we were able to view the specific details of both the volume group and logical volume.

LVM allows for great flexibility in managing your storage space and with these commands, you can easily manage the space on your hard disk.

Extending the Filesystem Mounted on the System

Now that we have extended the logical volume, let’s move on to extending the filesystem mounted on the system. Once we have extended the logical volume, the next step is to increase the size of the filesystem.

The easiest way to do this is by using the “resize2fs” command. This command is used to resize an ext2, ext3, or ext4 filesystem.

Mounting the Logical Volume and Displaying Filesystem Size

To mount the logical volume, we must first create a mount point, which is simply a folder that will act as the point of connection between the logical volume and the filesystem. We can create a mount point using the “mkdir” command.

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sudo mkdir /mnt/new_mount_point

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Next, we can mount the logical volume on the newly created mount point using the “mount” command. “`

sudo mount /dev/VG1/LV1 /mnt/new_mount_point

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Once the logical volume is mounted, we can use the “df” command to check the current size of the filesystem.

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sudo df -h

“`

This command will display the size of all mounted filesystems, including the newly mounted logical volume.

Extending the Filesystem Size Using resize2fs Command

Now that we have successfully mounted the logical volume, we can move on to resizing the filesystem using the “resize2fs” command. The syntax for this command is as follows:

“`

sudo resize2fs [Logical Volume Path] [New Size]

“`

For example, if we want to increase the size of our filesystem to 50GB, we would enter the following command:

“`

sudo resize2fs /dev/VG1/LV1 50G

“`

This command will extend the size of our filesystem to 50GB.

Verifying Filesystem Size Extension Using df Command

Once the “resize2fs” command is complete, we can use the “df” command again to verify that the filesystem has indeed been extended. “`

sudo df -h

“`

This command will display the new size of the filesystem, which should match the size specified in the “resize2fs” command.

Responsibilities of a System Administrator Related to Logical Volume Size Management

As a system administrator, it is important to have a thorough understanding of LVM and its various components. Logical volume size management is an essential part of system administration, especially in environments where data storage requirements are constantly changing.

It is the responsibility of a system administrator to ensure that there is enough storage space available on the system to meet the needs of the applications and users that rely on it.

Guide on How to Add a New Disk to Extend the Logical Volume and File System

To add a new disk to extend the logical volume and file system, we must first create a new physical volume on the disk using the “pvcreate” command as explained earlier in this article. Once the physical volume is created, we can extend the volume group using the “vgextend” command.

Once the volume group is extended, we can extend the logical volume using the “lvextend” command. Finally, we can extend the filesystem size using the “resize2fs” command.

To summarize, the following steps can be taken to add a new disk and extend the logical volume and file system:

1. Attach a new disk to the system and create a physical volume using the “pvcreate” command.

2. Extend the volume group to include the new physical volume using the “vgextend” command.

3. Extend the logical volume to include the new space using the “lvextend” command.

4. Extend the filesystem size using the “resize2fs” command.

Conclusion

In conclusion, Logical Volume Management is a flexible technique that allows system administrators to easily manage storage space on their systems. By following the steps outlined in this article, system administrators can add a new disk to their system, create a physical volume, and extend the logical volume and filesystem size.

This is an essential skill for anyone who works with Unix or Linux systems and needs to manage storage space on the system. In conclusion, Logical Volume Management is a crucial tool for system administrators to effectively manage storage space on their systems.

By understanding the pre-requisites, such as physical volumes, volume groups, and logical volumes, administrators can successfully increase the size of their logical volumes using LVM. Additionally, extending the volume group and logical volume can be achieved using commands like vgextend and lvextend.

Mounting the logical volume and resizing the filesystem using commands like mount, df, and resize2fs complete the process. The responsibilities of a system administrator related to logical volume size management are highlighted, emphasizing the importance of staying organized and adaptable.

Adding a new disk to extend the logical volume and file system is also covered. It is essential for system administrators to be proficient in LVM and its various components to ensure efficient storage management.

By following the procedures outlined in this article, administrators can successfully extend their storage capabilities and accommodate changing storage needs. The ability to effectively manage logical volume sizes is a valuable skill that contributes to the overall performance and scalability of Unix and Linux systems.

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