Chapter 2. Managing LVM physical volumes

Procedure

1. Identify the storage device you want to use as a physical volume. To list all available storage devices, use:

   $ lsblk

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2. Create an LVM physical volume:

   # pvcreate /dev/sdb

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   Replace /dev/sdb with the name of the device you want to initialize as a physical volume.

Procedure

1. Create a playbook file, for example, ~/playbook.yml, with the following content:

   ---
   - name: Manage local storage
     hosts: managed-node-01.example.com
     tasks:
       - name: Resize LVM PV size
         ansible.builtin.include_role:
           name: redhat.rhel_system_roles.storage
         vars:
           storage_pools:
              - name: myvg
                disks: ["sdf"]
                type: lvm
                grow_to_fill: true

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   The settings specified in the example playbook include the following:

   grow_to_fill

   true The role automatically expands the storage volume to use any new capacity on the disk.

   false The role leaves the storage volume at its current size, even if the underlying disk has grown.

   For details about all variables used in the playbook, see the /usr/share/ansible/roles/rhel-system-roles.storage/README.md file on the control node.

2. Validate the playbook syntax:

   $ ansible-playbook --syntax-check ~/playbook.yml

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   Note that this command only validates the syntax and does not protect against a wrong but valid configuration.

3. Run the playbook:

   $ ansible-playbook ~/playbook.yml

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Verification

1. Verify the grow_to_fill setting works as expected. Prepare a test PV and VG:

   # pvcreate /dev/sdf
   # vgcreate myvg /dev/sdf

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2. Check and record the initial physical volume size:

   # pvs

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3. Edit the playbook to set grow_to_fill: false and run the playbook.
4. Check the volume size and verify that it remained unchanged.
5. Edit the playbook to set grow_to_fill: true and re-run the playbook.
6. Check the volume size and verify that it has expanded.

Procedure

1. List the physical volumes to identify the device you want to remove:

   # pvs
   
     PV           VG Fmt  Attr PSize  PFree
     /dev/sdb       lvm2 ---  28.87g 28.87g

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2. Remove the physical volume:

   # pvremove /dev/sdb

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   Replace /dev/sdb with the name of the device associated with the physical volume.

   Note

   If your physical volume is part of the volume group, you need to remove it from the volume group first.

   • If you volume group contains more that one physical volume, use the vgreduce command:

     # vgreduce VolumeGroupName /dev/sdb

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     Replace VolumeGroupName with the name of the volume group. Replace /dev/sdb with the name of the device.

   • If your volume group contains only one physical volume, use the vgremove command:

     # vgremove VolumeGroupName

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     Replace VolumeGroupName with the name of the volume group.

Procedure

1. Log in to the RHEL 10 web console.
2. Click Storage.
3. In the Storage table, click the volume group in which you want to create logical volumes.
4. On the Logical volume group page, scroll to the LVM2 logical volumes section and click Create new logical volume.
5. In the Name field, enter a name for the new logical volume. Do not include spaces in the name.

6. In the Purpose drop-down menu, select Block device for filesystems.

   This configuration enables you to create a logical volume with the maximum volume size which is equal to the sum of the capacities of all drives included in the volume group.

7. Define the size of the logical volume. Consider:

   • How much space the system using this logical volume will need.
   • How many logical volumes you want to create.

   You do not have to use the whole space. If necessary, you can grow the logical volume later.

8. Click Create.

   The logical volume is created. To use the logical volume you must format and mount the volume.

Procedure

1. Log in to the RHEL 10 web console.
2. Click Storage.
3. In the Storage table, click the volume group in the logical volumes is created.
4. On the Logical volume group page, scroll to the LVM2 logical volumes section.
5. Click the menu button, ⋮, next to the volume group you want to format.
6. From the drop-down menu, select Format.
7. In the Name field, enter a name for the file system.
8. In the Mount Point field, add the mount path.

9. In the Type drop-down menu, select a file system:

   • XFS file system supports large logical volumes, switching physical drives online without outage, and growing an existing file system. Leave this file system selected if you do not have a different strong preference.

     XFS does not support reducing the size of a volume formatted with an XFS file system.

   • ext4 file system supports:

     • Logical volumes
     • Switching physical drives online without an outage
     • Growing a file system
     • Shrinking a file system

10. Select the Overwrite existing data with zeros checkbox if you want the RHEL web console to rewrite the whole disk with zeros. This option is slower because the program has to go through the whole disk, but it is more secure. Use this option if the disk includes any data and you need to overwrite it.

    If you do not select the Overwrite existing data with zeros checkbox, the RHEL web console rewrites only the disk header. This increases the speed of formatting.

11. From the Encryption drop-down menu, select the type of encryption if you want to enable it on the logical volume.

    You can select a version with either the LUKS1 (Linux Unified Key Setup) or LUKS2 encryption, which allows you to encrypt the volume with a passphrase.

12. In the At boot drop-down menu, select when you want the logical volume to mount after the system boots.
13. Select the required Mount options.

14. Format the logical volume:

    • If you want to format the volume and immediately mount it, click Format and mount.

    • If you want to format the volume without mounting it, click Format only.

      Formatting can take several minutes depending on the volume size and which formatting options are selected.

Verification

1. On the Logical volume group page, scroll to the LVM2 logical volumes section and click the logical volume to check the details and additional options.
2. If you selected the Format only option, click the menu button at the end of the line of the logical volume, and select Mount to use the logical volume.

Procedure

1. Log in to the RHEL 10 web console.
2. Click Storage.
3. In the Storage table, click the volume group in the logical volumes is created.
4. On the Logical volume group page, scroll to the LVM2 logical volumes section and click the menu button, ⋮, next to volume group you want to resize.

5. From the menu, select Grow or Shrink to resize the volume:

   • Growing the Volume:

     1. Select Grow to increase the size of the volume.
     2. In the Grow logical volume dialog box, adjust the size of the logical volume.

     3. Click Grow.

        LVM grows the logical volume without causing a system outage.

   • Shrinking the Volume:

     1. Select Shrink to reduce the size of the volume.
     2. In the Shrink logical volume dialog box, adjust the size of the logical volume.

     3. Click Shrink.

        LVM shrinks the logical volume without causing a system outage.