12.2.3. 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 12.2. Creating pre-formatted block device storage pools using virsh

  1. 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 and mount points are now created.

  2. Verify the new pool

    List the present storage pools. 
    # virsh pool-list --all
Name                 State      Autostart
-----------------------------------------
default              active     yes
guest_images_fs      inactive   no

  3. 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

  4. 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

  5. Turn on autostart

    By default, a storage pool defined with virsh, is not set to automatically start each time libvirtd starts. To remedy this, enable the automatic start with the virsh pool-autostart command. The storage pool is now automatically started each time libvirtd starts. 
    # virsh pool-autostart guest_images_fs
Pool guest_images_fs marked as autostarted

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

  6. 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