Trilium supports simple backup scheme where it saves copy of the document on these events:

• once a day
• once a week
• once a month
• before DB migration to newer version

So in total you'll have at most 4 backups from different points in time which should protect you from various problems. These backups are stored by default in backup directory placed in the data directory.

This is only very basic backup solution, and you're encouraged to add some better backup solution - e.g. backing up the document to cloud / different computer etc.

Note that synchronization provides also some backup capabilities by its nature of distributing the data to other computers.

Let's assume you want to restore the weekly backup, here's how to do it:

• find data directory Trilium uses - easy way is to open "About Trilium Notes" from "Menu" in upper left corner and looking at "data directory"
  • I'll refer to ~/trilium-data as data directory from now on
• find ~/trilium-data/backup/backup-weekly.db - this is the document backup
• at this point stop/kill Trilium
• delete ~/trilium-data/document.db, ~/trilium-data/document.db-wal and ~/trilium-data/document.db-shm (latter two files are auto generated)
• copy and rename this ~/trilium-data/backup/backup-weekly.db to ~/trilium-data/document.db
• make sure that the file is writable, e.g. with chmod 600 document.db
• start Trilium again

If you have configured sync then you need to do it across all members of the sync cluster, otherwise older version (restored backup) of the document will be detected and synced to the newer version.

Although this is not recommended, it is possible to disable backup in config.ini in the data directory:

[General]

... some other configs

# set to true to disable backups (e.g. because of limited space on server)
noBackup=true

See sample config.