I now see it is nextcloud.log and the subsequent .1 (which is now 8.9GB), this results in a full partition after a few days and then logrotate or something fixes it. But looking at the logs it is complaining constantly about a few things in very verbose log lines (long SQL queries)
{"reqId":"q8lmwJWo1GAhdGAP97bZ","level":0,"time":"2026-07-23T11:01:42+00:00","remoteAddr":"::1","user":"--","app":"no app in context","method":"GET","url":"/apps/richdocuments/settings/fonts.json","scriptName":"/index.php","message":"OCA\\Richdocuments\\Controller\\SettingsController::getJsonFontList uses the @NoCSRFRequired annotation and should use the #[OCP\\AppFramework\\Http\\Attribute\\NoCSRFRequired] attribute instead","userAgent":"COOLWSD HTTP Agent 26.04.1.4","version":"34.0.1.2","data":[]}
{"reqId":"SCwxor6xrEX1Z9giRxBB","level":1,"time":"2026-07-23T11:01:49+00:00","remoteAddr":"::1","user":"simon","app":"no app in context","method":"PROPFIND","url":"/remote.php/dav/files/simon/","scriptName":"/remote.php","message":"The app config key dav/enableCalendarFederation is not defined in the config lexicon","userAgent":"Mozilla/5.0 (Linux) mirall/3.16.7-1~deb13u1 (Debian built) (Nextcloud, debian-6.12.95+deb13-amd64 ClientArchitecture: x86_64 OsArchitecture: x86_64)","version":"34.0.1.2","clientReqId":"7caf0af3-6c73-40b7-91d3-f7cbc0c20c1a","data":[]}
{"reqId":"SCwxor6xrEX1Z9giRxBB","level":1,"time":"2026-07-23T11:01:49+00:00","remoteAddr":"::1","user":"simon","app":"no app in context","method":"PROPFIND","url":"/remote.php/dav/files/simon/","scriptName":"/remote.php","message":"The app config key dav/sendInvitations is not defined in the config lexicon","userAgent":"Mozilla/5.0 (Linux) mirall/3.16.7-1~deb13u1 (Debian built) (Nextcloud, debian-6.12.95+deb13-amd64 ClientArchitecture: x86_64 OsArchitecture: x86_64)","version":"34.0.1.2","clientReqId":"7caf0af3-6c73-40b7-91d3-f7cbc0c20c1a","data":[]}
{"reqId":"IlRgtupIdtm0N7u2Ma4E","level":1,"time":"2026-07-23T11:01:50+00:00","remoteAddr":"::1","user":"simon","app":"no app in context","method":"PROPFIND","url":"/remote.php/dav/files/simon/","scriptName":"/remote.php","message":"The app config key dav/enableCalendarFederation is not defined in the config lexicon","userAgent":"Mozilla/5.0 (Linux) mirall/3.16.7-1~deb13u1 (Debian built) (Nextcloud, debian-6.12.95+deb13-amd64 ClientArchitecture: x86_64 OsArchitecture: x86_64)","version":"34.0.1.2","clientReqId":"56fe2b5a-65a5-4925-bc55-18dd1b02c55e","data":[]}
{"reqId":"IlRgtupIdtm0N7u2Ma4E","level":1,"time":"2026-07-23T11:01:50+00:00","remoteAddr":"::1","user":"simon","app":"no app in context","method":"PROPFIND","url":"/remote.php/dav/files/simon/","scriptName":"/remote.php","message":"The app config key dav/sendInvitations is not defined in the config lexicon","userAgent":"Mozilla/5.0 (Linux) mirall/3.16.7-1~deb13u1 (Debian built) (Nextcloud, debian-6.12.95+deb13-amd64 ClientArchitecture: x86_64 OsArchitecture: x86_64)","version":"34.0.1.2","clientReqId":"56fe2b5a-65a5-4925-bc55-18dd1b02c55e","data":[]}
{"reqId":"h2aWySsqiUqSjA1rvwFr","level":0,"time":"2026-07-23T11:02:11+00:00","remoteAddr":"::1","user":"simon","app":"dav","method":"GET","url":"/ocs/v2.php/apps/user_status/api/v1/user_status?format=json","scriptName":"/ocs/v2.php","message":"No calendar events found for status check","userAgent":"Mozilla/5.0 (Linux) mirall/3.16.7-1~deb13u1 (Debian built) (Nextcloud, debian-6.12.95+deb13-amd64 ClientArchitecture: x86_64 OsArchitecture: x86_64)","version":"34.0.1.2","clientReqId":"190a4e09-6eb3-46ef-82a8-83f7d37eee69","data":{"app":"dav","user":"simon"}}
{"reqId":"JoDdUTUZFXxwpu8OypFT","level":0,"time":"2026-07-23T11:02:19+00:00","remoteAddr":"::1","user":"simon","app":"no app in context","method":"GET","url":"/ocs/v2.php/apps/notifications/api/v2/notifications","scriptName":"/ocs/v2.php","message":"dirty table reads: SELECT `name` FROM `*PREFIX*authtoken` WHERE (`uid` = :dcValue1) AND (`last_activity` >= :dcValue2)","userAgent":"Mozilla/5.0 (X11; Linux x86_64; rv:152.0) Gecko/20100101 Firefox/152.0","version":"34.0.1.2","exception":{"Exception":"Exception","Message":"dirty table reads: SELECT `name` FROM `*PREFIX*authtoken` WHERE (`uid` = :dcValue1) AND (`last_activity` >= :dcValue2)","Code":0,"Trace":[{"file":"/var/www/nextcloud/lib/private/DB/ConnectionAdapter.php","line":57,"function":"executeQuery","class":"OC\\DB\\Connection","type":"->"},{"file":"/var/www/nextcloud/lib/private/DB/QueryBuilder/QueryBuilder.php","line":261,"function":"executeQuery","class":"OC\\DB\\ConnectionAdapter","type":"->"},{"file":"/var/www/nextcloud/apps/notifications/lib/Service/ClientService.php","line":37,"function":"executeQuery","class":"OC\\DB\\QueryBuilder\\QueryBuilder","type":"->"},{"file":"/var/www/nextcloud/apps/notifications/lib/Controller/EndpointController.php","line":94,"function":"hasTalkDesktop","class":"OCA\\Notifications\\Service\\ClientService","type":"->"},{"file":"/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php","line":165,"function":"listNotifications","class":"OCA\\Notifications\\Controller\\EndpointController","type":"->"},{"file":"/var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php","line":78,"function":"executeController","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->"},{"file":"/var/www/nextcloud/lib/private/AppFramework/App.php","line":137,"function":"dispatch","class":"OC\\AppFramework\\Http\\Dispatcher","type":"->"},{"file":"/var/www/nextcloud/lib/private/Route/Router.php","line":324,"function":"main","class":"OC\\AppFramework\\App","type":"::"},{"file":"/var/www/nextcloud/ocs/v1.php","line":63,"function":"match","class":"OC\\Route\\Router","type":"->"},{"file":"/var/www/nextcloud/ocs/v2.php","line":10,"args":["/var/www/nextcloud/ocs/v1.php"],"function":"require_once"}],"File":"/var/www/nextcloud/lib/private/DB/Connection.php","Line":407,"message":"dirty table reads: SELECT `name` FROM `*PREFIX*authtoken` WHERE (`uid` = :dcValue1) AND (`last_activity` >= :dcValue2)","tables":"[\"oc_authtoken\"]","reads":"[\"oc_authtoken\"]","exception":"{\"class\":\"Exception\",\"message\":\"dirty table reads: SELECT `name` FROM `*PREFIX*authtoken` WHERE (`uid` = :dcValue1) AND (`last_activity` >= :dcValue2)\",\"code\":0,\"file\":\"/var/www/nextcloud/lib/private/DB/Connection.php:407\",\"trace\":\"#0 /var/www/nextcloud/lib/private/DB/ConnectionAdapter.php(57): OC\\DB\\Connection->executeQuery()\\n#1 /var/www/nextcloud/lib/private/DB/QueryBuilder/QueryBuilder.php(261): OC\\DB\\ConnectionAdapter->executeQuery()\\n#2 /var/www/nextcloud/apps/notifications/lib/Service/ClientService.php(37): OC\\DB\\QueryBuilder\\QueryBuilder->executeQuery()\\n#3 /var/www/nextcloud/apps/notifications/lib/Controller/EndpointController.php(94): OCA\\Notifications\\Service\\ClientService->hasTalkDesktop()\\n#4 /var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php(165): OCA\\Notifications\\Controller\\EndpointController->listNotifications()\\n#5 /var/www/nextcloud/lib/private/AppFramework/Http/Dispatcher.php(78): OC\\AppFramework\\Http\\Dispatcher->executeController()\\n#6 /var/www/nextcloud/lib/private/AppFramework/App.php(137): OC\\AppFramework\\Http\\Dispatcher->dispatch()\\n#7 /var/www/nextcloud/lib/private/Route/Router.php(324): OC\\AppFramework\\App::main()\\n#8 /var/www/nextcloud/ocs/v1.php(63): OC\\Route\\Router->match()\\n#9 /var/www/nextcloud/ocs/v2.php(10): require_once('...')\\n#10 {main}\"}","CustomMessage":"dirty table reads: SELECT `name` FROM `*PREFIX*authtoken` WHERE (`uid` = :dcValue1) AND (`last_activity` >= :dcValue2)"}}
{"reqId":"EEaTxhQvLxuOcS0AgH5o","level":1,"time":"2026-07-23T11:02:20+00:00","remoteAddr":"::1","user":"simon","app":"no app in context","method":"PROPFIND","url":"/remote.php/dav/files/simon/","scriptName":"/remote.php","message":"The app config key dav/enableCalendarFederation is not defined in the config lexicon","userAgent":"Mozilla/5.0 (Linux) mirall/3.16.7-1~deb13u1 (Debian built) (Nextcloud, debian-6.12.95+deb13-amd64 ClientArchitecture: x86_64 OsArchitecture: x86_64)","version":"34.0.1.2","clientReqId":"9f1bec37-5646-47a8-9d34-1a1d62fd896f","data":[]}
{"reqId":"EEaTxhQvLxuOcS0AgH5o","level":1,"time":"2026-07-23T11:02:20+00:00","remoteAddr":"::1","user":"simon","app":"no app in context","method":"PROPFIND","url":"/remote.php/dav/files/simon/","scriptName":"/remote.php","message":"The app config key dav/sendInvitations is not defined in the config lexicon","userAgent":"Mozilla/5.0 (Linux) mirall/3.16.7-1~deb13u1 (Debian built) (Nextcloud, debian-6.12.95+deb13-amd64 ClientArchitecture: x86_64 OsArchitecture: x86_64)","version":"34.0.1.2","clientReqId":"9f1bec37-5646-47a8-9d34-1a1d62fd896f","data":[]}