Working with LVM Storage

Hands-On Lab

 

Photo of Rob Marti

Rob Marti

Linux Training Architect I in Content

Length

00:30:00

Difficulty

Intermediate

In this lab, we’re going to go over the LVM management tool. These are skills that will serve you well in your career as a Linux sysadmin. Once complete, you’ll have a solid understanding of how to use these tools.

What are Hands-On Labs?

Hands-On Labs are scenario-based learning environments where learners can practice without consequences. Don't compromise a system or waste money on expensive downloads. Practice real-world skills without the real-world risk, no assembly required.

Working with LVM Storage

Introduction

In this lab we’re going to go over LVM managent tool. These are skills that will serve you well in your career as a Linux sysadmin. Once complete, you’ll have a solid understanding of how to use these tools.

Scenario

We've been tasked with creating a large logical volume out of the two disks attached to this server. The volume group name should be RHCSA. The Logical Volume name should be pinehead and should be 3 GB in size.

Make sure that the resulting logical volume is formatted as XFS, and persistently mounted at /mnt/lvol.

After that is complete, we should grow the logical volume and the filesystem by 200 MB.

Get Logged in

Use the credentials and server IP in the hands-on lab overview page to log in to our lab server. Once we're in, we can get moving. Since we'll need to be root for the all of the commands, we'll run a quick sudo -i as soon as we're in. Once that's done, we can get moving.

Create a Physical Device

To see the names of our disks, we need to run fdisk -l. Then we run pvcreate /dev/xvdg /dev/xvdf to create the physical devices. To check how it went, we can do a quick pvs or pvdisplay, and we'll see that they've been created.

Create a Volume Group

All we need to do is run vgcreate RHCSA /dev/xvdg /dev/xvdf. RHCSA is going to be the name of our volume group, and those physical devices we created in the last step is where this volume group will go.

Create a Logical Volume

Now we can create the our logical volume using the lvcreate command:

[root@host]# lvcreate -n pinehead -L 3G RHCSA
  • -n denotes the name of the LV
  • -L denotes the size of the LV
  • RHCSA is the name of the Volume Group we're creating this LV in

Format the LV as XFS and Mount It Persistently at /mnt/lvol

Now we can format the disk like any other device. To format it as XFS, we'll run:

[root@host]# mkfs.xfs /dev/mapper/RHCSA-pinehead

We've got to create a mount point:

mkdir /mnt/lvol

Before we can get it mounting persistently (after reboots), we need the UUID. Run blkid to get it, then copy it. We'll need it in a second.

Edit /etc/fstab (with whichever text editor you prefer) and create a new line that looks like this:

UUID="&ltTHE_UUID_WE_COPIED>" /mnt/lvol xfs defaults 0 0

Now, to mount everything listed in fstab (including this new mount we just created), let's run mount -a.

Grow the Mount Point by 200 MB

To grow an LV, we can run:

[root@host]# lvextend -L+200M /dev/RHCSA/pinehead

We can let the LVM tools automatically resize the filesystem as well by passing the -r or --resizefs flags.

Optionally, we could have run a growfs command to resize the filesystem:

[root@host]# xfs_growfs /mnt/lvol

Conclusion

We did it. We created a logical volume, got it to mount persistently, and then made it a little bigger. These are exactly the things we set out to do. Congratulations!