Merge pull request #2975 from restic/rawtaz-doc-resume

Add FAQ on whether restic can resume backups
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rawtaz 2020-10-03 23:12:34 +02:00 committed by GitHub
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@ -3,6 +3,32 @@ FAQ
This is the list of Frequently Asked Questions for restic.
Will restic resume an interrupted backup?
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Yes, restic will resume interrupted backups when they are re-run.
When backing up, restic periodically writes index files to keep a record of
the uploaded data. Even if there's no snapshot created in the end (due to the
backup being interrupted), these indexes are stored in the repository for the
data that has been uploaded so far. Next time restic runs, it is then able to
find the uploaded data through these indexes, and thereby reference it again
without having to upload it a second time. This effectively makes it continue
from where it saved the last index, which should be up to a few minutes ago.
It does not matter if the backup was interrupted by the user or if it was due
to unforeseen circumstances such as connectivity issues, power loss, etc.
Simply re-run the backup again and restic should only upload what it needs to
in order to complete the interrupted backup and create a snapshot.
Note however that during the initial backup run and any re-tries, until there
has been a first snapshot created for the backup set (list of files and
directories to be backed up), restic will need to re-scan the files on disk as
there is no parent snapshot to compare the filesystem with to determine which
files have changed. This process should however be far quicker than the
uploading, and it's normal to see restic scan the files again when re-running
the backup.
``restic check`` reports packs that aren't referenced in any index, is my repository broken?
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