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.\" Man page generated from reStructuredText.
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-.TH BORG-CHECK 1 "2019-11-01" "" "borg backup tool"
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+.TH BORG-CHECK 1 "2020-04-12" "" "borg backup tool"
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.SH NAME
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borg-check \- Check repository consistency
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.
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@@ -40,24 +40,25 @@ The check command verifies the consistency of a repository and the corresponding
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First, the underlying repository data files are checked:
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.INDENT 0.0
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.IP \(bu 2
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-For all segments the segment magic (header) is checked
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+For all segments, the segment magic header is checked.
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.IP \(bu 2
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-For all objects stored in the segments, all metadata (e.g. crc and size) and
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+For all objects stored in the segments, all metadata (e.g. CRC and size) and
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all data is read. The read data is checked by size and CRC. Bit rot and other
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types of accidental damage can be detected this way.
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.IP \(bu 2
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-If we are in repair mode and a integrity error is detected for a segment,
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-we try to recover as many objects from the segment as possible.
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+In repair mode, if an integrity error is detected in a segment, try to recover
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+as many objects from the segment as possible.
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.IP \(bu 2
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-In repair mode, it makes sure that the index is consistent with the data
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-stored in the segments.
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+In repair mode, make sure that the index is consistent with the data stored in
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+the segments.
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.IP \(bu 2
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-If you use a remote repo server via ssh:, the repo check is executed on the
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-repo server without causing significant network traffic.
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+If checking a remote repo via \fBssh:\fP, the repo check is executed on the server
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+without causing significant network traffic.
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.IP \(bu 2
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The repository check can be skipped using the \fB\-\-archives\-only\fP option.
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.IP \(bu 2
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-A repository check can be time consuming. Partial checks are possible with the \fB\-\-max\-duration\fP option.
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+A repository check can be time consuming. Partial checks are possible with the
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+\fB\-\-max\-duration\fP option.
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.UNINDENT
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.sp
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Second, the consistency and correctness of the archive metadata is verified:
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@@ -66,46 +67,46 @@ Second, the consistency and correctness of the archive metadata is verified:
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Is the repo manifest present? If not, it is rebuilt from archive metadata
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chunks (this requires reading and decrypting of all metadata and data).
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.IP \(bu 2
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-Check if archive metadata chunk is present. if not, remove archive from
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-manifest.
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+Check if archive metadata chunk is present; if not, remove archive from manifest.
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.IP \(bu 2
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For all files (items) in the archive, for all chunks referenced by these
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-files, check if chunk is present.
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-If a chunk is not present and we are in repair mode, replace it with a same\-size
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-replacement chunk of zeros.
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-If a previously lost chunk reappears (e.g. via a later backup) and we are in
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-repair mode, the all\-zero replacement chunk will be replaced by the correct chunk.
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-This requires reading of archive and file metadata, but not data.
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+files, check if chunk is present. In repair mode, if a chunk is not present,
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+replace it with a same\-size replacement chunk of zeroes. If a previously lost
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+chunk reappears (e.g. via a later backup), in repair mode the all\-zero replacement
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+chunk will be replaced by the correct chunk. This requires reading of archive and
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+file metadata, but not data.
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.IP \(bu 2
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-If we are in repair mode and we checked all the archives: delete orphaned
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-chunks from the repo.
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+In repair mode, when all the archives were checked, orphaned chunks are deleted
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+from the repo. One cause of orphaned chunks are input file related errors (like
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+read errors) in the archive creation process.
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.IP \(bu 2
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-if you use a remote repo server via ssh:, the archive check is executed on
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-the client machine (because if encryption is enabled, the checks will require
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-decryption and this is always done client\-side, because key access will be
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-required).
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+If checking a remote repo via \fBssh:\fP, the archive check is executed on the
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+client machine because it requires decryption, and this is always done client\-side
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+as key access is needed.
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.IP \(bu 2
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-The archive checks can be time consuming, they can be skipped using the
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+The archive checks can be time consuming; they can be skipped using the
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\fB\-\-repository\-only\fP option.
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.UNINDENT
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.sp
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-The \fB\-\-max\-duration\fP option can be used to split a long\-running repository check into multiple partial checks.
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-After the given number of seconds the check is interrupted. The next partial check will continue where the
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-previous one stopped, until the complete repository has been checked. Example: Assuming a full check took 7
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-hours, then running a daily check with \-\-max\-duration=3600 (1 hour) would result in one full check per week.
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+The \fB\-\-max\-duration\fP option can be used to split a long\-running repository check
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+into multiple partial checks. After the given number of seconds the check is
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+interrupted. The next partial check will continue where the previous one stopped,
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+until the complete repository has been checked. Example: Assuming a full check took 7
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+hours, then running a daily check with \-\-max\-duration=3600 (1 hour) resulted in one
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+full check per week.
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.sp
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-Attention: Partial checks can only do way less checks than a full check (only the CRC32 checks on segment file
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-entries are done) and cannot be combined with \fB\-\-repair\fP\&. Partial checks may therefore be useful only with very
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-large repositories where a full check would take too long. Doing a full repository check aborts a partial check;
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-the next partial check will start from the beginning.
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+Attention: Partial checks can only do way less checking than a full check (only the
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+CRC32 checks on segment file entries are done), and cannot be combined with the
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+\fB\-\-repair\fP option. Partial checks may therefore be useful only with very large
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+repositories where a full check took too long. Doing a full repository check aborts a
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+partial check; the next partial check will restart from the beginning.
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.sp
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The \fB\-\-verify\-data\fP option will perform a full integrity verification (as opposed to
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checking the CRC32 of the segment) of data, which means reading the data from the
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repository, decrypting and decompressing it. This is a cryptographic verification,
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which will detect (accidental) corruption. For encrypted repositories it is
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-tamper\-resistant as well, unless the attacker has access to the keys.
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-.sp
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-It is also very slow.
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+tamper\-resistant as well, unless the attacker has access to the keys. It is also very
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+slow.
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.SH OPTIONS
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.sp
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See \fIborg\-common(1)\fP for common options of Borg commands.
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