该系统有非常旧的靴子（2 年和 3 年），它们没有回收利用，我无法对其进行吸尘：
$ journalctl --list-boots --no-pager
-16 53baf678f0d749d6b390afea4a3ef96b Wed 2014-04-02 22:07:26 IDT—Wed 2014-04-02 22:46:08 IDT
-15 60a54132f5c8450d9b33a77819a037d1 Thu 2014-04-03 00:04:50 IDT—Thu 2014-04-03 12:30:21 IDT
-14 24b65a7e589d4479bf5020b98b8120b7 Wed 2015-04-01 03:10:01 IDT—Wed 2015-04-01 08:35:21 IDT
-13 43398d6d74c849bcb359a2d3963f4aaa Wed 2015-04-08 00:26:31 IDT—Wed 2015-04-08 00:26:31 IDT
-12 51b28f394cbb4699b2c4098297f73b2e Mon 2017-07-24 18:28:02 IDT—Mon 2017-07-24 19:08:37 IDT
-11 67467a640fb5413189f9cd518a56f668 Tue 2017-07-25 01:21:00 IDT—Mon 2017-07-24 22:54:40 IDT
-10 1370875e2f2c4b3c80c82901367b0835 Tue 2017-07-25 03:05:18 IDT—Tue 2017-07-25 01:18:51 IDT
-9 462c24a6b4cd487c834e121240bb880c Tue 2017-07-25 13:16:02 IDT—Tue 2017-07-25 18:50:32 IDT …