borg upgrade

borg [common options] upgrade [options] [REPOSITORY]
positional arguments
  REPOSITORY path to the repository to be upgraded
  -n, --dry-run do not change repository
  --inplace rewrite repository in place, with no chance of going back to older versions of the repository.
  --force Force upgrade
  --tam Enable manifest authentication (in key and cache) (Borg 1.0.9 and later).
  --disable-tam Disable manifest authentication (in key and cache).
  --archives-tam add TAM authentication for all archives.

Common options


Upgrade an existing, local Borg repository.

When you do not need borg upgrade

Not every change requires that you run borg upgrade.

You do not need to run it when:

  • moving your repository to a different place
  • upgrading to another point release (like 1.0.x to 1.0.y), except when noted otherwise in the changelog
  • upgrading from 1.0.x to 1.1.x, except when noted otherwise in the changelog

Borg 1.x.y upgrades

Archive TAM authentication:

Use borg upgrade --archives-tam REPO to add archive TAMs to all archives that are not TAM authenticated yet. This is a convenient method to just trust all archives present - if an archive does not have TAM authentication yet, a TAM will be added. Archives created by old borg versions < 1.0.9 do not have TAMs. Archives created by newer borg version should have TAMs already. If you have a high risk environment, you should not just run this, but first verify that the archives are authentic and not malicious (== have good content, have a good timestamp). Borg 1.2.5+ needs all archives to be TAM authenticated for safety reasons.

This upgrade needs to be done once per repository.

Manifest TAM authentication:

Use borg upgrade --tam REPO to require manifest authentication introduced with Borg 1.0.9 to address security issues. This means that modifying the repository after doing this with a version prior to 1.0.9 will raise a validation error, so only perform this upgrade after updating all clients using the repository to 1.0.9 or newer.

This upgrade should be done on each client for safety reasons.

If a repository is accidentally modified with a pre-1.0.9 client after this upgrade, use borg upgrade --tam --force REPO to remedy it.

If you routinely do this you might not want to enable this upgrade (which will leave you exposed to the security issue). You can reverse the upgrade by issuing borg upgrade --disable-tam REPO.

See for details.

Attic and Borg 0.xx to Borg 1.x

This currently supports converting an Attic repository to Borg and also helps with converting Borg 0.xx to 1.0.

Currently, only LOCAL repositories can be upgraded (issue #465).

Please note that borg create (since 1.0.0) uses bigger chunks by default than old borg or attic did, so the new chunks won’t deduplicate with the old chunks in the upgraded repository. See --chunker-params option of borg create and borg recreate.

borg upgrade will change the magic strings in the repository’s segments to match the new Borg magic strings. The keyfiles found in $ATTIC_KEYS_DIR or ~/.attic/keys/ will also be converted and copied to $BORG_KEYS_DIR or ~/.config/borg/keys.

The cache files are converted, from $ATTIC_CACHE_DIR or ~/.cache/attic to $BORG_CACHE_DIR or ~/.cache/borg, but the cache layout between Borg and Attic changed, so it is possible the first backup after the conversion takes longer than expected due to the cache resync.

Upgrade should be able to resume if interrupted, although it will still iterate over all segments. If you want to start from scratch, use borg delete over the copied repository to make sure the cache files are also removed:

borg delete borg

Unless --inplace is specified, the upgrade process first creates a backup copy of the repository, in REPOSITORY.before-upgrade-DATETIME, using hardlinks. This requires that the repository and its parent directory reside on same filesystem so the hardlink copy can work. This takes longer than in place upgrades, but is much safer and gives progress information (as opposed to cp -al). Once you are satisfied with the conversion, you can safely destroy the backup copy.

WARNING: Running the upgrade in place will make the current copy unusable with older version, with no way of going back to previous versions. This can PERMANENTLY DAMAGE YOUR REPOSITORY! Attic CAN NOT READ BORG REPOSITORIES, as the magic strings have changed. You have been warned.


# Upgrade the borg repository to the most recent version.
$ borg upgrade -v /path/to/repo
making a hardlink copy in /path/to/repo.before-upgrade-2016-02-15-20:51:55
opening attic repository with borg and converting
no key file found for repository
converting repo index /path/to/repo/index.0
converting 1 segments...
converting borg 0.xx to borg current
no key file found for repository

Upgrading a passphrase encrypted attic repo

attic offered a “passphrase” encryption mode, but this was removed in borg 1.0 and replaced by the “repokey” mode (which stores the passphrase-protected encryption key into the repository config).

Thus, to upgrade a “passphrase” attic repo to a “repokey” borg repo, 2 steps are needed, in this order:

  • borg upgrade repo
  • borg key migrate-to-repokey repo