Hi Satish,

Which version of openstack are you using?

In bobcat (glance_store version 4.6.0) we have added a feature [1] RBD Trash to cover the issue you described.

Pre bobcat (glance_store version < 4.6.0), deletion of snapshot will fail with the issue you described.

[1] https://docs.openstack.org/releasenotes/glance_store/2023.2.html#relnotes-4-6-0-stable-2023-2

Thanks & Best Regards,

Abhishek Kekane

On Wed, Jan 24, 2024 at 10:26 PM Satish Patel <satish.txt@gmail.com> wrote:

Folks,

I have two openstack clouds and both have their own Ceph backend storage.I am trying to migrate instances from openstack A to openstack B. 

1. Take a snapshot from A

2.  Export snapshot and import to B 

3. Create instance on B 

4. Delete snapshot - (I am getting error because its in-use) 

Because it has a parent reference to that volume. How do I remove the reference so it will let me delete a snapshot. Reason I am asking is because I have so many VMs to migrate and don't want glance to have 100s of entities in those snapshots. 

What is the alternative here? I can try qcow2 if that is the final solution to make it clean. 

# rbd -p volumes info volume-f2b2aec2-cc57-49e5-aca1-54b5a7ee9f3a
rbd image 'volume-f2b2aec2-cc57-49e5-aca1-54b5a7ee9f3a':
	size 40 GiB in 5120 objects
	order 23 (8 MiB objects)
	snapshot_count: 0
	id: 5473c827864fed
	block_name_prefix: rbd_data.5473c827864fed
	format: 2
	features: layering, exclusive-lock, object-map, fast-diff, deep-flatten
	op_features:
	flags:
	create_timestamp: Fri Jan 19 19:03:25 2024
	access_timestamp: Wed Jan 24 15:51:04 2024
	modify_timestamp: Wed Jan 24 15:52:40 2024
	parent: images/3708f961-fb74-49f1-ab9b-40cf7954abed@snap
	overlap: 40 GiB