{"id":8722,"date":"2025-06-22T19:32:42","date_gmt":"2025-06-22T17:32:42","guid":{"rendered":"https:\/\/milchyn.cz\/?page_id=8722"},"modified":"2025-09-22T10:44:01","modified_gmt":"2025-09-22T10:44:01","slug":"limitace-journal-logu","status":"publish","type":"page","link":"https:\/\/milchyn.cz\/limitace-journal-logu","title":{"rendered":"Syst\u00e9mov\u00e9 journal logy"},"content":{"rendered":"<p style=\"text-align: right;\"><em>Xubuntu 24.04.2 LTS<\/em><\/p>\n<a id=\"co_jsou_journal_logy\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-5\">Co jsou journal logy<\/div><div id=\"mch-acr-content-5\" class=\"mch-acr-content\" hidden><\/p>\n<p>Jsou to z\u00e1znamy o \u010dinnostech a chyb\u00e1ch syst\u00e9mu, slu\u017eeb, aplikac\u00ed, kter\u00e9 spravuje slu\u017eba systemd-journald, sou\u010d\u00e1st syst\u00e9mu systemd. Na rozd\u00edl od textov\u00fdch log\u016f<em> (\/var\/log\/syslog, \/var\/log\/messages)<\/em>, jsou journal logy ulo\u017een\u00e9 v bin\u00e1rn\u00edm form\u00e1tu, kter\u00fd je operativn\u011bj\u0161\u00ed a efektivn\u011bj\u0161\u00ed. Nahrazuje nebo dopl\u0148uje tradi\u010dn\u00ed syslog.<\/p>\n<p><\/div><\/div>\n<a id=\"jak_logy_prohl\u00ed\u017eet\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-6\">Jak logy prohl\u00ed\u017eet<\/div><div id=\"mch-acr-content-6\" class=\"mch-acr-content\" hidden><\/p>\n<table style=\"border-collapse: collapse;width: 100%;height: 197px\">\n<tbody>\n<tr style=\"height: 22px\">\n<td style=\"width: 34.9743%;height: 22px\">\ud83d\udcbb <code>sudo journalctl<\/code><\/td>\n<td style=\"width: 65.0257%;height: 22px\">\ud83d\udca1 Zobraz\u00ed v\u0161echny z\u00e1znamy od nejstar\u0161\u00edch po nejnov\u011bj\u0161\u00ed.<\/td>\n<\/tr>\n<tr style=\"height: 22px\">\n<td style=\"width: 34.9743%;height: 22px\">\ud83d\udcbb <code>sudo journalctl -r<\/code><\/td>\n<td style=\"width: 65.0257%;height: 22px\">\ud83d\udca1 Nejnov\u011bj\u0161\u00ed z\u00e1znamy na za\u010d\u00e1tku.<\/td>\n<\/tr>\n<tr style=\"height: 22px\">\n<td style=\"width: 34.9743%;height: 22px\">\ud83d\udcbb <code>sudo journalctl -f<\/code><\/td>\n<td style=\"width: 65.0257%;height: 22px\">\ud83d\udca1 Zobrazuje nov\u00e9 z\u00e1znamy v re\u00e1ln\u00e9m \u010dase <em>(jako tail -f)<\/em> a nejde kombinovat s<em><code>-r<\/code><\/em><\/td>\n<\/tr>\n<tr style=\"height: 22px\">\n<td style=\"width: 34.9743%;height: 22px\">\ud83d\udcbb <code>sudo journalctl -b<\/code><\/td>\n<td style=\"width: 65.0257%;height: 22px\">\ud83d\udca1 Zobraz\u00ed z\u00e1znamy za posledn\u00ed boot.<\/td>\n<\/tr>\n<tr style=\"height: 22px\">\n<td style=\"width: 34.9743%;height: 22px\">\ud83d\udcbb <code>sudo journalctl -b -1<\/code><\/td>\n<td style=\"width: 65.0257%;height: 22px\">\ud83d\udca1 Zobraz\u00ed z\u00e1znamy za p\u0159edchoz\u00ed boot.<\/td>\n<\/tr>\n<tr style=\"height: 22px\">\n<td style=\"width: 34.9743%;height: 22px\">\ud83d\udcbb <code>sudo journalctl --since &quot;yesterday&quot;<\/code><\/td>\n<td style=\"width: 65.0257%;height: 22px\">\ud83d\udca1 Zobraz\u00ed v\u010derej\u0161\u00ed z\u00e1znamy.<\/td>\n<\/tr>\n<tr style=\"height: 22px\">\n<td style=\"width: 34.9743%;height: 22px\">\ud83d\udcbb <code>sudo journalctl -u sshd.service<\/code><\/td>\n<td style=\"width: 65.0257%;height: 22px\">\ud83d\udca1 Zobraz\u00ed filtrovan\u00e9 z\u00e1znamy podle slu\u017eby<em> (nap\u0159. sshd)<\/em><\/td>\n<\/tr>\n<tr style=\"height: 22px\">\n<td style=\"width: 34.9743%;height: 22px\">\ud83d\udcbb <code>sudo journalctl -p err<\/code><\/td>\n<td style=\"width: 65.0257%;height: 22px\">\ud83d\udca1 Zobraz\u00ed jen z\u00e1znamy chyb.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><strong>\u261d\ufe0f<\/strong> Bez <code>sudo<\/code> se zobraz\u00ed pouze z\u00e1znamy od aktu\u00e1ln\u00edho u\u017eivatele.<\/p>\n<p><\/div><\/div>\n<a id=\"pro\u010d_je_limitovat\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-7\">Pro\u010d je limitovat<\/div><div id=\"mch-acr-content-7\" class=\"mch-acr-content\" hidden><\/p>\n<p>Journal samoz\u0159ejm\u011b m\u00e1 svou kalkulovanou limitaci, kter\u00e1 nedopust\u00ed zapln\u011bn\u00ed diskov\u00e9ho prostoru, ale pro b\u011b\u017en\u00fd u\u017eivatelsk\u00fd po\u010d\u00edta\u010d se m\u016f\u017ee zmen\u0161it. Ka\u017edop\u00e1dn\u011b na nastaven\u00e9 velikosti z\u00e1vis\u00ed mno\u017estv\u00ed uchovan\u00fdch z\u00e1znam\u016f a do jak\u00e9 historie. Odmaz\u00e1vaj\u00ed se nejstar\u0161\u00ed z\u00e1znamy.<\/p>\n<p><\/div><\/div>\n<a id=\"nastaven\u00ed_limit\u016f\"><\/a><div class=\"mch-acr\"><div class=\"mch-acr-title\" role=\"button\" tabindex=\"0\" aria-expanded=\"false\" aria-controls=\"mch-acr-content-8\">Nastaven\u00ed limit\u016f<\/div><div id=\"mch-acr-content-8\" class=\"mch-acr-content\" hidden><\/p>\n<p>V p\u0159\u00edkladu uv\u00e1d\u00edm nastaven\u00ed <em>(SystemMaxUse=100M)<\/em> pro uchov\u00e1n\u00ed v\u00edce jak 10 tis\u00edc z\u00e1znam\u016f.<\/p>\n<p><strong>\u261d\ufe0f<\/strong> U\u017eivatel mus\u00ed m\u00edt administr\u00e1torsk\u00e9 opr\u00e1vn\u011bn\u00ed<em> (\u010dlen sudo)<\/em>.<\/p>\n<ol>\n<li>\ud83d\udcbb <code>sudo journalctl --disk-usage<\/code><br \/>\nZji\u0161t\u011bn\u00ed velikosti journal log\u016f p\u0159ed odmaz\u00e1n\u00edm.<\/li>\n<li>\ud83d\udcbb <code>sudo mousepad \/etc\/systemd\/journald.conf<\/code><br \/>\nEditace konfigura\u010dn\u00edho souboru.<\/li>\n<li>\u2026\u270d\ufe0f <samp>SystemMaxUse=100M<\/samp><br \/>\nOmezuje celkovou velikost v\u0161ech logovac\u00edch soubor\u016f systemd-journalu ulo\u017een\u00fdch na disku <em>(ve \/var\/log\/journal) <\/em>na 100 MB.<\/li>\n<li>\u2026\u270d\ufe0f <code>&lt;samp&gt;SystemMaxFileSize=10M&lt;\/samp&gt;<\/code><br \/>\nOmezuje maxim\u00e1ln\u00ed velikost jednoho journal souboru na 10 MB.<\/li>\n<li>\u2026\u270d\ufe0f <code>&lt;samp&gt;ForwardToSyslog=no&lt;\/samp&gt;<\/code><br \/>\nZak\u00e1\u017ee p\u0159epos\u00edl\u00e1n\u00ed journald log\u016f do syslog d\u00e9mona <em>(nap\u0159. rsyslog nebo syslog-ng)<\/em> a t\u00edmto zamez\u00ed duplikov\u00e1n\u00ed log\u016f.<\/li>\n<li>Ukon\u010den\u00ed editace, potvrdit ulo\u017eit.<\/li>\n<\/ol>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-8723 alignnone\" src=\"https:\/\/milchyn.cz\/wp-content\/uploads\/2025\/06\/xub2404-journal-01-e1750612462138.png\" alt=\"\" width=\"550\" height=\"400\" srcset=\"https:\/\/milchyn.cz\/wp-content\/uploads\/2025\/06\/xub2404-journal-01-e1750612462138.png 550w, https:\/\/milchyn.cz\/wp-content\/uploads\/2025\/06\/xub2404-journal-01-e1750612462138-300x218.png 300w\" sizes=\"auto, (max-width: 550px) 100vw, 550px\" \/><\/p>\n<ol>\n<li>\ud83d\udcbb <code>sudo systemctl restart systemd-journald<\/code><br \/>\nAktivace zm\u011bn konfigurace.<\/li>\n<li>\ud83d\udcbb <code>sudo journalctl --vacuum-size=100M<\/code><br \/>\nOdmazan\u00ed \u00a0journal log\u016f.<\/li>\n<li>\ud83d\udcbb <code>sudo journalctl --disk-usage<\/code><br \/>\nKontroln\u00ed zji\u0161t\u011bn\u00ed velikosti journal log\u016f po odmaz\u00e1n\u00ed.<\/li>\n<\/ol>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-8724 alignnone\" src=\"https:\/\/milchyn.cz\/wp-content\/uploads\/2025\/06\/xub2404-journal-02-e1750612543325.png\" alt=\"\" width=\"576\" height=\"370\" srcset=\"https:\/\/milchyn.cz\/wp-content\/uploads\/2025\/06\/xub2404-journal-02-e1750612543325.png 576w, https:\/\/milchyn.cz\/wp-content\/uploads\/2025\/06\/xub2404-journal-02-e1750612543325-300x193.png 300w\" sizes=\"auto, (max-width: 576px) 100vw, 576px\" \/><\/p>\n<p><\/div><\/div>\n","protected":false},"excerpt":{"rendered":"<p>Xubuntu 24.04.2 LTS<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":8713,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-8722","page","type-page","status-publish","hentry"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v26.1.1 - 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