Comment # 1 on bug 1226415 from Stefan Seyfried

This is "journalctl -u systemd-journald.service" from the boot doing the update
and the one after the update:

-- Boot e02bb8c9070e4203a25fff312819c90a --
Jun 11 10:10:07 server systemd-journald[178]: Journal started
Jun 11 10:10:07 server systemd-journald[178]: Runtime Journal
(/run/log/journal/63ab585aac31189cc7872956493ee6b3) is 8.0M, max 792.4M, 784.4M
free.
Jun 11 10:10:10 server systemd-journald[178]: Journal stopped
Jun 11 10:10:10 server systemd-journald[659]: Journal started
Jun 11 10:10:10 server systemd-journald[659]: Runtime Journal
(/run/log/journal/63ab585aac31189cc7872956493ee6b3) is 8.0M, max 792.4M, 784.4M
free.
Jun 11 10:10:10 server systemd[1]: systemd-journald.service: Deactivated
successfully.
Jun 11 10:10:11 server systemd-journald[659]: Time spent on flushing to
/var/log/journal/63ab585aac31189cc7872956493ee6b3 is 17.007ms for 1194 entries.
Jun 11 10:10:11 server systemd-journald[659]: System Journal
(/var/log/journal/63ab585aac31189cc7872956493ee6b3) is 6.5G, max 6.5G, 0B free.
Jun 16 09:55:13 server systemd-journald[659]: Journal stopped
Jun 16 09:55:13 server systemd-journald[24981]: Collecting audit messages is
disabled.
Jun 16 09:55:13 server systemd-journald[24981]: File
/var/log/journal/63ab585aac31189cc7872956493ee6b3/system.journal corrupted or
uncleanly shut down, renaming and replacing.
Jun 16 09:55:13 server systemd-journald[24981]: Journal started
Jun 16 09:55:13 server systemd-journald[24981]: System Journal
(/var/log/journal/63ab585aac31189cc7872956493ee6b3) is 800.4M, max 818.2M,
17.7M free.
Jun 16 10:00:16 server systemd-journald[24981]: File
/var/log/journal/63ab585aac31189cc7872956493ee6b3/user-10329.journal corrupted
or uncleanly shut down, renaming and replacing.
-- Boot 8b04d845e4144a64a73b3479dac75401 --
Jun 16 10:06:33 server systemd-journald[189]: /etc/systemd/journald.conf:52:
Failed to parse size value, ignoring: 10%
Jun 16 10:06:33 server systemd-journald[189]: Collecting audit messages is
disabled.
Jun 16 10:06:33 server systemd-journald[189]: Journal started
Jun 16 10:06:33 server systemd-journald[189]: Runtime Journal
(/run/log/journal/63ab585aac31189cc7872956493ee6b3) is 8.0M, max 792.6M, 784.6M
free.
Jun 16 10:06:36 server systemd-journald[189]: Journal stopped
Jun 16 10:06:37 server systemd-journald[691]: /etc/systemd/journald.conf:52:
Failed to parse size value, ignoring: 10%
Jun 16 10:06:37 server systemd-journald[691]: Collecting audit messages is
disabled.
Jun 16 10:06:37 server systemd-journald[691]: Journal started
Jun 16 10:06:37 server systemd-journald[691]: Runtime Journal
(/run/log/journal/63ab585aac31189cc7872956493ee6b3) is 8.0M, max 792.6M, 784.6M
free.
Jun 16 10:06:37 server systemd[1]: systemd-journald.service: Deactivated
successfully.
Jun 16 10:06:40 server systemd-journald[691]: Time spent on flushing to
/var/log/journal/63ab585aac31189cc7872956493ee6b3 is 78.220ms for 1279 entries.
Jun 16 10:06:40 server systemd-journald[691]: System Journal
(/var/log/journal/63ab585aac31189cc7872956493ee6b3) is 817.2M, max 6.5G, 5.7G
free.
Jun 16 10:06:40 server systemd-journald[691]: Received client request to flush
runtime journal.
Jun 16 10:06:40 server systemd-journald[691]:
/var/log/journal/63ab585aac31189cc7872956493ee6b3/system.journal: Journal file
uses a different sequence number ID, rotating.
Jun 16 10:06:40 server systemd-journald[691]: Rotating system journal.
Jun 16 10:06:54 server systemd-journald[691]:
/var/log/journal/63ab585aac31189cc7872956493ee6b3/user-10329.journal: Journal
file uses a different sequence number ID, rotating.

Note that at June 15, 9:55:13 it does not even complain about the invalid 10%
value, so it seems to ignore the system config during the update.