Comment 2 for bug 1906784

- cinder version is N.
- Cinder management driver is ceph(rbd).
- Only sometimes，no distinction between command line and page.
- Under normal circumstances there will also be the following output
”“”
2020-11-20 13:46:33.181939 7f42d250bd40 -1 Errors while parsing config file!
2020-11-20 13:46:33.181945 7f42d250bd40 -1 read_conf: ignoring line 3 because it doesn't end with a newline! Please end the config file witha newline.
“”“

The reason why the size exceeds 64k is rbd image enabled striping feature, stderr will print repeat rate of progress when execu rbd export-diff.
so we report a bug :
https://github.com/ceph/ceph/pull/38399
https://tracker.ceph.com/issues/48431
Now the bug has been fixed, but for code robustness, should cinder also consider stderr overflow scenarios?