I found a merge request, ceph mon has new optíon :mon_sync_max_payload_keys https://github.com/ceph/ceph/commit/d6037b7f484e13cfc9136e63e4cf7fac6ad68960... My value of options mon_sync_max_payload_size is 4096. If mon_sync_max_payload_keys options is default, ceph mon may be not sync because slow opt. What do you think?