Hey inyong, You are more than welcome to create a specification for us to discuss the details. This is where you can start[1]. Next week we're going to have a Virtual PTG (projects team gathering)[2], where you can bring the topic to the table so we can discuss You can açso find us on the #cinder channel on OFTC. Erlon _____________________ [1] https://wiki.openstack.org/wiki/Cinder/how-to-contribute-new-feature [2] https://ptg.openinfra.org/ Em ter., 14 de abr. de 2026 às 10:49, 홍인용 <inyong.hong@samsung.com> escreveu:

Hi all,

I would like to suggest improving Cinder's incremental backup efficiency by introducing a Changed Block Tracking (CBT) interface.

Currently, incremental backups read the full volume and rely on chunk-level SHA256 hashing to detect changes. Even when only a small portion of the volume has changed, a full scan is still required, which impacts performance and resource usage.

Some backends like Ceph (rbd diff) and NetApp (SnapDiff) already have native APIs for tracking block-level changes. I believe it is worth exploring a standardized CBT interface at the backup driver level to take advantage of these capabilities—with a fallback to the current hashing method for drivers that do not support it.

I am interested in exploring this further and would appreciate your thoughts on this approach or if there have been similar discussions in the past.

Thanks, inyong hong(hong-p)