rbd export-diff/import-diff hangs

Hi, I'm using rbd import and export to copy image from one cluster to another. Also using import-diff and export-diff to update image in remote cluster. For example, "rbd --cluster local export-diff ... | rbd --cluster remote import-diff ...". Sometimes, the whole command is stuck. I can't tell it's stuck on which end of the pipe. I did some search, [1] seems the same issue and [2] is also related. Wonder if there is any way to identify where it's stuck and get more debugging info. Given [2], I'd suspect the import-diff is stuck, cause rbd client is importing to the remote cluster. Networking latency could be involved here? Ping latency is 7~8 ms. Any comments is appreciated! [1] https://bugs.launchpad.net/cinder/+bug/2031897 [2] https://stackoverflow.com/questions/69858763/ceph-rbd-import-hangs Thanks! Tony