Configure the Optional Image Conversion File System

By default, qcow2 to raw image-conversion is done using the docker_lv file system. To avoid filling up the docker_lv file system, you can create a new file system dedicated for image conversion as described in this section.


  • The requested size of the image-conversion file system should be big enough to accommodate any image that is uploaded to Glance.

  • The recommended size for the file system must be at least twice as large as the largest converted image from qcow2 to raw.

  • The conversion file system can be added before or after stx-openstack is applied.

  • The conversion file system must be added on both controllers. Otherwise, stx-openstack will not use the new file system.

  • If the conversion file system is added after stx-openstack is applied, changes to stx-openstack will only take effect once the application is reapplied.

  • The image-conversion file system can only be added on the controllers, and must be added, with the same size, to both controllers. Alarms will be raised, if:

    • The conversion file system is not added on both controllers.

    • The size of the file system is not the same on both controllers.

Adding a New Filesystem for Image-Conversion

  1. Use the host-fs-add command to add a file system dedicated to qcow2 to raw image-conversion.

    ~(keystone_admin)]$ system host-fs-add <hostname or id> <fs-name=size>


    hostname or id

    is the location where the file system will be added


    is the file system name


    is an integer indicating the file system size in Gigabytes

    For example:

    ~(keystone_admin)]$ system host-fs-add controller-0 image-conversion=8
    | Property       | Value                                |
    | uuid           | 52bfd1c6-93b8-4175-88eb-a8ee5566ce71 |
    | name           | image-conversion                     |
    | size           | 8                                    |
    | logical_volume | conversion-lv                        |
    | created_at     | 2020-09-18T17:08:54.413424+00:00     |
    | updated_at     | None                                 |
  2. When the image-conversion filesystem is added, a new partition /opt/conversion is created and mounted.

  3. Use the following command to list the file systems.

    ~(keystone_admin)]$ system host-fs-list controller-0
    | UUID               | FS Name          | Size in GiB | Logical Volume |
    | b5ffb565-4af2-4f26 | backup           | 25          | backup-lv      |
    | a52c5c9f-ec3d-457c | docker           | 30          | docker-lv      |
    | 52bfd1c6-93b8-4175 | image-conversion | 8           | conversion-lv  |
    | a2fabab2-054d-442d | kubelet          | 10          | kubelet-lv     |
    | 2233ccf4-6426-400c | scratch          | 16          | scratch-lv     |

Resizing the File System

You can change the size of the image-conversion file system at runtime using the following command:

~(keystone_admin)]$ system host-fs-modify <hostname or id> <fs-name=size>

For example:

~(keystone_admin)]$ system host-fs-modify controller-0 image-conversion=8

Removing the File System

  1. You can remove an image-conversion file system dedicated to qcow2 image-conversion using the following command:

    ~(keystone_admin)]$ system host-fs-delete <hostname-or-id> <fs-name>
  2. When the image-conversion file system is removed from the system, the /opt/conversion partition is also removed.


You cannot delete an image-conversion file system when stx-openstack is in the applying,**applied**, or removing state.

You cannot add or remove any other file systems using these commands.