Chapter 20. Configuring thin logical volumes using the web console

You can use thin-provisioned logical volumes to allocate more space for designated applications or servers than the actually available physical storage.

For details, see Creating thin-provisioned snapshot volumes.

The following sections describe:

Prerequisites

  • The RHEL 8 web console has been installed.

    For details, see Installing the web console.

  • The cockpit-storaged package is installed on your system.
  • Physical drives or other types of storage devices, which you want to use to create volume groups, are attached to your system.

20.1. Creating pools for thin logical volumes in the web console

Create a pool for thin-provisioned volumes.

Prerequisites

Procedure

  1. Log in to the RHEL 8 web console.
  2. Click Storage.
  3. Click the volume group in which you want to create thin volumes.
  4. Click Create new Logical Volume.
  5. In the Name field, enter a name for the new pool of thin volumes without spaces.
  6. In the Purpose drop down menu, select Pool for thin-provisioned volumes. This configuration enables you to create the thin volume.
  7. Define the size of the pool of thin volumes. Consider:

    • How many thin volumes you will need in this pool?
    • What is the expected size of each thin volume?

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

  8. Click Create.

    The pool for thin volumes has been created and you can add thin volumes.

20.2. Creating thin logical volumes in the web console

Create a thin logical volume in the pool. The pool can include multiple thin volumes and each thin volume can be as large as the pool for thin volumes itself.

Important

Using thin volumes requires regular checkup of actual free physical space of the logical volume.

Prerequisites

Procedure

  1. Log in to the RHEL 8 web console.
  2. Click Storage.
  3. Click the volume group in which you want to create thin volumes.
  4. Click the desired pool.
  5. Click Create Thin Volume.
  6. In the Create Thin Volume dialog box, enter a name for the thin volume without spaces.
  7. Define the size of the thin volume.
  8. Click Create.

At this stage, the thin logical volume has been created and you need to format it.

20.3. Formatting logical volumes in the web console

Logical volumes act as physical drives. To use them, you must format them with a file system.

Warning

Formatting logical volumes erases all data on the volume.

The file system you select determines the configuration parameters you can use for logical volumes. For example, the XFS file system does not support shrinking volumes. For details, see Resizing logical volumes in the web console.

Prerequisites

Procedure

  1. Log in to the RHEL 8 web console.
  2. Click Storage.
  3. In the Devices section, click the volume group in which the logical volume is placed.
  4. In the Logical volumes section, click Format.

    Image displaying the details of the existing logical volumes.

  5. In the Name field, enter a name for the file system.
  6. In the Mount Point field, add the mount path.

    The format a logical volume dialog box with configurable fields.

  7. 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
  8. Based on how you want to format the volume, select the Overwrite option:

    • Do not overwrite existing data — the RHEL web console rewrites only the disk header. The advantage of this option is the short time required for the formatting process.
    • Overwrite existing data with zeros — the RHEL web console rewrites the whole disk with zeros. This option is slower because the program has to go through the whole disk. Use this option if the disk includes any data and you need to overwrite it.
  9. In 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.

  10. In the At boot drop-down menu, select when you want the logical volume to mount after the system boots.
  11. Select the required Mount options.
  12. 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. After the formatting completes successfully, you can see the details of the formatted logical volume on the Filesystem tab.

    cockpit lv formatted

  2. If you had selected the Format only option, click Mount to use the logical volume.

20.4. Using the web console to create thin-provisioned snapshot volumes

You can create snapshots of thin logical volumes in the RHEL web console to backup changes recorded on the disk from the last snapshot.

Prerequisites

Procedure

  1. Log in to the RHEL web console. For more information, see Logging in to the web console.
  2. In the RHEL web console, click Storage.
  3. In the Devices box, click the volume group that contains the required logical volume.
  4. Find the volume in the Logical volumes table and click the menu button on its line.
  5. Click Create snapshot.

    Image displaying the drop-down menu for a logical volume.

  6. In the Name field, enter a snapshot name.

    Image displaying the Create snapshot dialog box.

  7. Click Create.
  8. Find the new snapshot in the Logical volumes table and click Activate to activate the volume.

    Image displaying the new logical volume in the Logical volumes table.