Noticed this while investigating the parent task, it looks like the (quite long) log line below can be found locally on ms-be /var/log/swift/background.log file but not on centrallog hosts:
Oct 5 12:14:55 ms-be2017 object-replicator: Killing long-running rsync: ['rsync', '--recursive', '--whole-file', '--human-readable', '--xattrs', '--itemize-changes', '--ignore-existing', '--timeout=30', '--contimeout=30', '--bwlimit=0', '--exclude=.*.[0-9a-zA-Z][0-9a-zA-Z][0-9a-zA-Z][0-9a-zA-Z][0-9a-zA-Z][.... the whole rsync log line]
The line is suspiciously around 64k in length:
root@ms-be2017:/var/log/swift# grep 'Killing' background.log.1 | head -1 | wc
1 1438 65558