Retype a volume

If you created a volume with the wrong storage type you are able to retype it.

Perhaps you’ve noticed that a disk was to heavily utilised causing IO-wait on your instance because it’s using HDD storage and want to change it to SSD. The other scenario might be a volume has grown and is to expensive to host on SSD.

Note

NVMe volumes are different, they are a local resource on the hypervisors and cannot be retyped. If you need to move to NVMe, you would need to setup a new instance based with NVMe, attach your volume, move the data to the local disk, then detach and delete the volume.

The following two requirements must be true to re-type a volume attached to an instance:

  • The instance must be running.

  • There must not be snapshots on the volume.

Any deviations will cause a silent fail. A volume that is not attached also cant have any snapshots but will otherwise be possible to just retype at convenience.

A retype can take hours to complete depending on the size of the volume, the instance is available during this time but can have reduced IO during the swap-over.

We recommend doing this procedure during the night time (when IO is likely less).

Important

As retyping involves copying all the data of the instance, we strongly recommend first backing it up before proceeding.

Cloud management portal

Its currently not possible to retype volumes by using the cloud management portal.

OpenStack Horizon

To retype a volume by using OpenStack Horizon

  • Under Project, click Compute and then Instances in the sidebar menu.

  • Press the name of the instance from which you want to remove a volume.

  • At the bottom, under the Volumes attached section, press the volume you want to retype.

  • Select Change volume type in the dropdown in the top right corner.

  • Select the new type.

  • In migration policy dropdown, select On-demand.

  • Press Change volume type

  • A progress bar will show during the retype operation (which can take hours depending on size).

OpenStack Terminal Client

To retype a volume by using the OpenStack Terminal Client

  • Run this command: openstack volume list, save the ID of the volume you want to retype.

  • Run this command: openstack volume type list, save the name of the new volume type you want to use (for example ssd or hdd).

  • Run this command: openstack volume set --type [TYPE_NAME] [VOLUME_ID] --retype-policy on-demand, replacing the items in angle brackets with the volume type name and the ID of the volume.

  • Run this command to verify: openstack volume show [VOLUME_ID] -c status, when the status changes from retyping, the retype is done.

See also