Description of problem: When incremental backup introduced, a new checkbox was added to the disk UI - 'enable incremental backup'. It was supposed to be used as a flag to distinct between disks that can be a part of an incremental backup and disks that cannot. For example, the following disks cannot be a part of incremental backup - raw disks, disks that not set by the user as 'enable incremental backup' in the UI or via REST-API. This behavior changed, when bug 1926888 was fixed, it is valid to create a backup that contains a mix of full and incremental backup disks. So now it is valid to have disks that will be part of incremental backup and disks that should have a full backup under the same backup operation. Due to that change, there is no need for the 'enable incremental backup' checkbox or the disk update via the REST-API, disk will have backup='incremental' in case the disk format is QCOW2 by default. We should keep the API to have backward-compatibility, so the behavior should be: - When creating a new disk -> setting the 'enable incremental backup' checkbox in the UI will have the same behavior as today, create a disk with QCOW2 format. - QCOW2 disk will always have backup='incremental', setting it to backup='none' will be grayed out in the UI and will do nothing when using the REST-API. - RAW disk will always have backup='none' and the option to set it in the UI will be grayed-out - Same as today. Version-Release number of selected component (if applicable): How reproducible: Steps to Reproduce: 1. 2. 3. Actual results: Expected results: Additional info:
The 'enable incremental backup' flag has no effect besides backward compatibility for marking to the backup vendor if a disk is marked as enabled for backup. The only important this is when a disk is created, if setting it as 'enable incremental backup' it sets the disk format to 'QCOW2' - this topic is discussed in bug 1915029. *** This bug has been marked as a duplicate of bug 1915029 ***