13.2. Partition-based Storage Pools

⁠13.2. Partition-based Storage Pools

This section covers using a pre-formatted block device, a partition, as a storage pool.

For the following examples, a host physical machine has a 500GB hard drive (/dev/sdc) partitioned into one 500GB partition (/dev/sdc1). We set up a storage pool for it using the procedure below.

⁠13.2.1. Creating a Partition-based Storage Pool Using virt-manager

This procedure creates a new storage pool using a partition of a storage device.

⁠

Procedure 13.1. Creating a partition-based storage pool with virt-manager

Set the File System to ext4
From a command window, enter the following command to set the file system to ext4
```
# mkfs.ext4 /dev/sdc1
```
Open the storage pool settings
1. In the virt-manager graphical interface, select the host physical machine from the main window.
  Open the Edit menu and select Connection Details
2. click the Storage tab of the Connection Details window.
  ⁠
  Figure 13.1. Storage tab
Create the new storage pool
1. Add a new pool (part 1)
  Press the + button (at the bottom of the window). The Add a New Storage Pool wizard appears.
  Choose a Name for the storage pool. This example uses the name guest_images_fs. Change the Type to fs: Pre-Formatted Block Device.
  ⁠
  Figure 13.2. Storage pool name and type
  Press the Forward button to continue.
2. Add a new pool (part 2)
  Change the Target Path, , and Source Path fields.
  ⁠
  Figure 13.3. Storage pool path
  ⁠Target Path
  Enter the location to mount the source device for the storage pool in the Target Path field. If the location does not already exist, virt-manager will create the directory.
  ⁠Source Path
  Enter the device in the Source Path field.
  This example uses the /dev/sdc1 device.
  Verify the details and press the Finish button to create the storage pool.
Verify the new storage pool
The new storage pool appears in the storage list on the left after a few seconds. Verify the size is reported as expected, 2.88 GB Free in this example. Verify the State field reports the new storage pool as Active.
Select the storage pool. In the Autostart field, click the On Boot check box. This will make sure the storage device starts whenever the libvirtd service starts.
⁠
Figure 13.4. Storage list confirmation
The storage pool is now created, close the Connection Details window.

⁠13.2.2. Deleting a Storage Pool Using virt-manager

This procedure demonstrates how to delete a storage pool.

To avoid any issues with other guest virtual machines using the same pool, it is best to stop the storage pool and release any resources in use by it. To do this, select the storage pool you want to stop and click at the bottom of the Storage window.
Delete the storage pool by clicking . This icon is only enabled if you stop the storage pool first.

⁠13.2.3. Creating a Partition-based Storage Pool Using virsh

This section covers creating a partition-based storage pool with the virsh command.

Warning

Do not use this procedure to assign an entire disk as a storage pool (for example, /dev/sdb). Guests should not be given write access to whole disks or block devices. Only use this method to assign partitions (for example, /dev/sdb1) to storage pools.

⁠

Procedure 13.2. Creating pre-formatted block device storage pools using virsh

Create the storage pool definition
Use the virsh pool-define-as command to create a new storage pool definition. There are three options that must be provided to define a pre-formatted disk as a storage pool:
⁠Partition name
The name parameter determines the name of the storage pool. This example uses the name guest_images_fs in the example below.
⁠device
The device parameter with the path attribute specifies the device path of the storage device. This example uses the partition /dev/sdc1.
⁠mountpoint
The mountpoint on the local file system where the formatted device will be mounted. If the mount point directory does not exist, the virsh command can create the directory.
The directory /guest_images is used in this example.
```
# virsh pool-define-as guest_images_fs fs - - /dev/sdc1 - "/guest_images"
Pool guest_images_fs defined
```
The new pool is now created.

Verify the new pool

List the present storage pools.

# virsh pool-list --all
Name                 State      Autostart
-----------------------------------------
default              active     yes
guest_images_fs      inactive   no

Create the mount point

Use the virsh pool-build command to create a mount point for a pre-formatted file system storage pool.

# virsh pool-build guest_images_fs
Pool guest_images_fs built
# ls -la /guest_images
total 8
drwx------.  2 root root 4096 May 31 19:38 .
dr-xr-xr-x. 25 root root 4096 May 31 19:38 ..
# virsh pool-list --all
Name                 State      Autostart
-----------------------------------------
default              active     yes
guest_images_fs      inactive   no

Start the storage pool

Use the virsh pool-start command to mount the file system onto the mount point and make the pool available for use.

# virsh pool-start guest_images_fs
Pool guest_images_fs started
# virsh pool-list --all
Name                 State      Autostart
-----------------------------------------
default              active     yes
guest_images_fs      active     no

Turn on autostart

By default, a storage pool is defined with virsh is not set to automatically start each time libvirtd starts. Turn on automatic start with the virsh pool-autostart command. The storage pool is now automatically started each time libvirtd starts.

# virsh pool-autostart guest_images_fss
Pool guest_images_fs marked as autostarted

# virsh pool-list --all
Name                 State      Autostart
-----------------------------------------
default              active     yes
guest_images_fs      active     yes

Verify the storage pool

Verify the storage pool was created correctly, the sizes reported are as expected, and the state is reported as running. Verify there is a "lost+found" directory in the mount point on the file system, indicating the device is mounted.

# virsh pool-info guest_images_fs
Name:           guest_images_fs
UUID:           c7466869-e82a-a66c-2187-dc9d6f0877d0
State:          running
Persistent:     yes
Autostart:      yes
Capacity:       458.39 GB
Allocation:     197.91 MB
Available:      458.20 GB
# mount | grep /guest_images
/dev/sdc1 on /guest_images type ext4 (rw)
# ls -la /guest_images
total 24
drwxr-xr-x.  3 root root  4096 May 31 19:47 .
dr-xr-xr-x. 25 root root  4096 May 31 19:38 ..
drwx------.  2 root root 16384 May 31 14:18 lost+found

⁠13.2.4. Deleting a Storage Pool Using virsh

To avoid any issues with other guest virtual machines using the same pool, it is best to stop the storage pool and release any resources in use by it.
```
# virsh pool-destroy guest_images_disk
```
Optionally, if you want to remove the directory where the storage pool resides use the following command:
```
# virsh pool-delete guest_images_disk
```
Remove the storage pool's definition
```
# virsh pool-undefine guest_images_disk
```