Table of Contents
This is intended to give new users of Duplicati some basic technical background to understand the Duplicati UI options a bit better.
Background
When Duplicati runs for the first time, it naturally needs to figure out what files you want it to backup.
- Duplicati looks at the list of files and directories you have defined in the backup settings (Tab "Source Data").
- Internally it then creates a list of all the files it finds in the directories you defined.
- This list can be huge and thus a database is created to hold the list of all the files you want to backup.
- Duplicati then starts with the actual backup process - it compresses and encrypts a bunch of files and copies the resulting file to your backup destination. In parallel it keeps track of what files have been processed, their size, change date etc. in this database. This is just the high level description. If you care for the real technical stuff, take a look at this. :-)
Impact
- If the local database is corrupted/out of sync/invalid/etc, your repeating backup operations will most likely fail. If this is the case, the error message in the Duplicati logs will most likely tell you to run a repair on the local database.
- A corrupted local database does NOT affect your remote backup data. The remote data is still there, it can most likely just not be updated any more. You will need to fix the local issue in order to maintain a current up to date backup.
- Some times, the repair may be unsuccessful. One option is then to remove/delete the local database and rebuild it using the "Repair local data base" option.
Duplicati data base
Duplicati keeps track of it's backup process with a local database. Sometimes this database can get out of sync with your actual backup data and you may need to use these options in the UI:
- Delete local data (will delete the local database)
- Repair local data base (fixes and rebuilds the database by checking the backed up files against your local files)
- Verify backup files (performs some basic consistency checks against some random backup data - not a full verify)
Database FAQ
1. Can I restore my data when my local database is corrupt or missing?
A: Yes, you can restore your Duplicati backup data from your remote location even when the Duplicati local database is missing or corrupt. The database mostly needed to keep track of what files are already backed up into the remote location and what changes to your local files will need to be sent to the remote backup location in the next backup run.
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