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command-line
performance
disk-usage
systemd
systemd-journald
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URL:
https://askubuntu.com/q/1012913
Title:
Systemd logs (`journalctl`) are too large and slow
ID:
/2018/03/08/Systemd-logs-__journalctl__-are-too-large-and-slow
Created:
March 8, 2018
Edited: December 1, 2022
Upload:
April 8, 2024
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systemd comes with a nifty vacuum cleaner
To limit log files to a specific size systemd provides a vacuum feature to “suck out” older information from log files. The parameters allowed are:
--vacuum-size=BYTES Reduce disk usage below specified size
--vacuum-files=INT Leave only the specified number of journal files
--vacuum-time=TIME Remove journal files older than specified time
For example to reduce 312 MB consumption down to 200 MB (or less) use:
$ sudo journalctl --vacuum-size=200M
Deleted archived journal /var/log/journal/d7b25a27fe064cadb75a2f2f6ca7764e/system@00056515dbdd9a4e-a6fe2ec77e516045.journal~ (56.0M).
Deleted archived journal /var/log/journal/d7b25a27fe064cadb75a2f2f6ca7764e/user-65534@00056515dbfe731d-b7bab56cb4efcbf6.journal~ (8.0M).
Deleted archived journal /var/log/journal/d7b25a27fe064cadb75a2f2f6ca7764e/user-1000@1bbb77599cf14c65a18af51646751696-000000000000064f-00056444d58433e1.journal (112.0M).
Vacuuming done, freed 176.0M of archived journals on disk.
Disk Space saved
The journalctl size is reduced substantially:
$ journalctl --disk-usage
Archived and active journals take up 136.0M on disk.
Size has dropped from 312 MB to 136 MB a savings of 176 MB and 64 MB more than expected. This is probably a one time anomaly due to an extraordinary large single log file. I’ll revise this answer after a month if new info arises.
Boot Logs reduced
The number of journalctl boot logs was 32 but now it is reduced to 26:
$ journalctl --list-boots
-26 0f230cc546fd4aec8f5233e0074ab3e1 Tue 2018-02-13 03:57:20 MST—Wed 2018-02-14
-25 c0d2c0141dd840cbab75d3c2254f8781 Wed 2018-02-14 22:59:13 MST—Sat 2018-02-17
-24 aafb2573a6374e019a7165cb8eee74a0 Sun 2018-02-18 06:02:03 MST—Mon 2018-02-19
-23 8462f1969c6f4d61973e7e245014b846 Mon 2018-02-19 04:16:53 MST—Sat 2018-02-24
-22 7f71ac2fb9714c49aa05989b741655f2 Sat 2018-02-24 04:24:36 MST—Sat 2018-02-24
-21 b12a48c363474e5fb39311a166a98d54 Sat 2018-02-24 04:28:09 MST—Sun 2018-02-25
-20 fbef1e659de64a0cbdcb9994f5a39457 Sun 2018-02-25 17:48:20 MST—Mon 2018-02-26
-19 3d9b4c10f98d4ef7aab1cb2baa9b74e1 Mon 2018-02-26 08:37:01 MST—Mon 2018-02-26
-18 4412b117dcc648aa9eceabcd0f205207 Mon 2018-02-26 08:38:00 MST—Mon 2018-02-26
-17 f6794cbb7fb24213a6f2c3e368f666a1 Mon 2018-02-26 08:39:12 MST—Mon 2018-02-26
-16 472f968506ed446ab12cf7abc65fa81a Mon 2018-02-26 08:49:37 MST—Mon 2018-02-26
-15 d575c609d82e4ecd8dcebb70d40160d7 Mon 2018-02-26 17:07:36 MST—Mon 2018-02-26
-14 878cfd9239a84dae80c62e7413c72951 Mon 2018-02-26 17:24:54 MST—Mon 2018-02-26
-13 7f9913c7dbff46ab9bbd7c2cbefc4d7d Mon 2018-02-26 17:35:19 MST—Mon 2018-02-26
-12 bf90829ef13a4e9fa1794bf0a88f4033 Mon 2018-02-26 17:45:12 MST—Wed 2018-02-28
-11 fb879a836c7c459ab27f6332bee6013b Wed 2018-02-28 03:56:29 MST—Wed 2018-02-28
-10 b0fec230765046f5bf3d654db1dc13ee Wed 2018-02-28 20:03:15 MST—Thu 2018-03-01
-9 72a2d6789eab4396be16348d9ead0408 Thu 2018-03-01 03:58:25 MST—Fri 2018-03-02
-8 8bccdc9b16124d26af05c34c8a30a0f5 Fri 2018-03-02 16:54:36 MST—Sat 2018-03-03
-7 40c2875db30349f5a9b1dfc849a47c05 Sat 2018-03-03 10:03:48 MST—Sat 2018-03-03
-6 781c79d2ec7946afba0fa2300e8ebe56 Sat 2018-03-03 10:04:34 MST—Sat 2018-03-03
-5 bb66dc875e414021940b7233072516d2 Sat 2018-03-03 17:43:08 MST—Tue 2018-03-06
-4 ba3bcfdc71584757b8bef9df16e7b0f6 Tue 2018-03-06 16:56:36 MST—Tue 2018-03-06
-3 60faa0fda99a4ef4b14b73c412d69e50 Tue 2018-03-06 17:00:47 MST—Tue 2018-03-06
-2 9b317bb8403344ca84dd2f288bc90410 Tue 2018-03-06 17:02:15 MST—Tue 2018-03-06
-1 dcb126be665a4531aae4312af7e51a34 Tue 2018-03-06 17:09:00 MST—Tue 2018-03-06
0 6a105af650d5442a9b03004165e58adf Tue 2018-03-06 17:42:45 MST—Wed 2018-03-07
Performance improved
The time to verify journalctl integrity is noticeably quicker:
Time has reduced from 10 seconds down to 4 seconds.
Credit to this Source.
Long Term Solutions
I’ve created a cron job to run the vacuum cleaner once a month.
Another option as mentioned in comments is to set SystemMaxUse=50M in /etc/systemd/journald.conf. There are actually four different places you can set the option:
/etc/systemd/journald.conf
/etc/systemd/journald.conf.d/*.conf
/run/systemd/journald.conf.d/*.conf
/usr/lib/systemd/journald.conf.d/*.conf
There are actually many options you can use for similar goals:
SystemMaxUse=, SystemKeepFree=, SystemMaxFileSize=, SystemMaxFiles=, RuntimeMaxUse=, RuntimeKeepFree=, RuntimeMaxFileSize=, RuntimeMaxFiles=
reload conf:
$ sudo systemctl restart systemd-journald