Comment 1 for bug 1971154

Alexander Binzxxxxxx,

We do not have much concrete performance data to analyze, so more information about the actual problem would be helpful. Please remember to update this bug report.

It is a good idea to improve this, but it needs a lot of consideration. We should address this area because there are still some vulnerabilities that we need to address with RBD including sector sizes (512 vs 4k). However, adding a new configuration value that allows developers to set arbitrary values is not necessarily the right solution.
Regarding question 2: Specifying the chunk size prevents situations where images cannot be moved between pools during migration, such as cinder<->glance, etc. However, it is a good question that should be investigated further.

This bug was discussed in the bug session this week: https://meetings.opendev.org/meetings/cinder_bs/2022/cinder_bs.2022-05-04-15.01.log.html#l-31