borg/docs/usage/check.rst.inc

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.. _borg_check:
borg check
----------
::
usage: borg check [-h] [-v] [--debug] [--lock-wait N] [--show-version]
[--show-rc] [--no-files-cache] [--umask M]
[--remote-path PATH] [--repository-only] [--archives-only]
[--repair] [--save-space] [--last N] [-P PREFIX]
[REPOSITORY_OR_ARCHIVE]
Check repository consistency
positional arguments:
REPOSITORY_OR_ARCHIVE
repository or archive to check consistency of
optional arguments:
-h, --help show this help message and exit
-v, --verbose, --info
enable informative (verbose) output, work on log level
INFO
--debug enable debug output, work on log level DEBUG
--lock-wait N wait for the lock, but max. N seconds (default: 1).
--show-version show/log the borg version
--show-rc show/log the return code (rc)
--no-files-cache do not load/update the file metadata cache used to
detect unchanged files
--umask M set umask to M (local and remote, default: 0077)
--remote-path PATH set remote path to executable (default: "borg")
--repository-only only perform repository checks
--archives-only only perform archives checks
--repair attempt to repair any inconsistencies found
--save-space work slower, but using less space
--last N only check last N archives (Default: all)
-P PREFIX, --prefix PREFIX
only consider archive names starting with this prefix
Description
~~~~~~~~~~~
The check command verifies the consistency of a repository and the corresponding archives.
First, the underlying repository data files are checked:
- For all segments the segment magic (header) is checked
- For all objects stored in the segments, all metadata (e.g. crc and size) and
all data is read. The read data is checked by size and CRC. Bit rot and other
types of accidental damage can be detected this way.
- If we are in repair mode and a integrity error is detected for a segment,
we try to recover as many objects from the segment as possible.
- In repair mode, it makes sure that the index is consistent with the data
stored in the segments.
- If you use a remote repo server via ssh:, the repo check is executed on the
repo server without causing significant network traffic.
- The repository check can be skipped using the --archives-only option.
Second, the consistency and correctness of the archive metadata is verified:
- Is the repo manifest present? If not, it is rebuilt from archive metadata
chunks (this requires reading and decrypting of all metadata and data).
- Check if archive metadata chunk is present. if not, remove archive from
manifest.
- For all files (items) in the archive, for all chunks referenced by these
files, check if chunk is present (if not and we are in repair mode, replace
it with a same-size chunk of zeros). This requires reading of archive and
file metadata, but not data.
- If we are in repair mode and we checked all the archives: delete orphaned
chunks from the repo.
- if you use a remote repo server via ssh:, the archive check is executed on
the client machine (because if encryption is enabled, the checks will require
decryption and this is always done client-side, because key access will be
required).
- The archive checks can be time consuming, they can be skipped using the
--repository-only option.