borg-create(1)

Name
borg-create - Creates a new archive.

SYNOPSIS

borg [common options] create [options] NAME [PATH...]

DESCRIPTION

This command creates a backup archive containing all files found while recursively traversing all specified paths. Paths are added to the archive as they are given, which means that if relative paths are desired, the command must be run from the correct directory.

The slashdot hack in paths (recursion roots) is triggered by using /./: /this/gets/stripped/./this/gets/archived means to process that fs object, but strip the prefix on the left side of ./ from the archived items (in this case, this/gets/archived will be the path in the archived item).

If a recursion root (a path given on the command line or in a patterns file) is a symlink, borg follows it and archives what it points to - using the path you gave. If current is a symlink pointing to the directory 20260801-2345, borg create ARCHIVE current thus archives current as a directory (with the metadata of 20260801-2345) and recurses into it, archiving the contained fs objects as current/.... As the archived paths do not change when the symlink target changes, the files cache keeps working for such backups.

Note that the symlink itself is then not in the archive (and neither is its target path), so restoring will create a real directory (or file) where the symlink was. If you want the symlink archived as a symlink, do not give it as a recursion root, but let borg find it while recursing (symlinks found that way are never followed). A recursion root that is a symlink with a non-existing target is skipped with a warning.

If you give both a symlink and its target as recursion roots, borg archives the fs objects only once, under the path given first (like for any other root given twice).

When specifying '-' as a path, borg will read data from standard input and create a file named 'stdin' in the created archive from that data. In some cases, it is more appropriate to use --content-from-command. See the section Reading from stdin below for details.

The archive will consume almost no disk space for files or parts of files that have already been stored in other archives.

The --tags option can be used to add a list of tags to the new archive.

The archive name does not need to be unique; you can and should use the same name for a series of archives. The unique archive identifier is its ID (hash), and you can abbreviate the ID as long as it is unique.

In the archive name, you may use the following placeholders: {now}, {utcnow}, {fqdn}, {hostname}, {user} and some others.

Backup speed is increased by not reprocessing files that are already part of existing archives and were not modified. The detection of unmodified files is done by comparing multiple file metadata values with previous values kept in the files cache.

This comparison can operate in different modes as given by --files-cache:

•   ctime,size,inode (default on POSIX systems)

•   mtime,size,inode (default on Windows)

•   ctime,size (ignore the inode number)

•   mtime,size (ignore the inode number)

•   rechunk,ctime (all files are considered modified - rechunk, cache ctime)

•   rechunk,mtime (all files are considered modified - rechunk, cache mtime)

•   disabled (disable the files cache, all files considered modified - rechunk)

    inode number: better safety, but often unstable on network filesystems

    Normally, detecting file modifications will take inode information into consideration to improve the reliability of file change detection. This is problematic for files located on sshfs and similar network file systems which do not provide stable inode numbers, such files will always be considered modified. You can use modes without inode in this case to improve performance, but reliability of change detection might be reduced.

    ctime vs. mtime: safety vs. speed

•   ctime is a rather safe way to detect changes to a file (metadata and contents) as it cannot be set from userspace. But a metadata-only change will already update the ctime, so there might be some unnecessary chunking/hashing even without content changes. Some filesystems do not support ctime (change time). E.g. doing a chown or chmod to a file will change its ctime.

•   mtime usually works and only updates if file contents were changed. But mtime can be arbitrarily set from userspace, e.g., to set mtime back to the same value it had before a content change happened. This can be used maliciously as well as well-meant, but in both cases mtime-based cache modes can be problematic.

    On Windows, ctime is the file creation time, not the "metadata change time" it is on POSIX systems. A ctime based mode would therefore not notice content changes of a file that keeps its size and inode number, so borg defaults to mtime,size,inode there. If a ctime based mode is given explicitly on Windows, borg warns and uses the corresponding mtime based mode instead: ctime,size,inode -> mtime,size,inode, ctime,size -> mtime,size, rechunk,ctime -> rechunk,mtime.

The --files-changed option controls how Borg detects if a file has changed during backup:

•   ctime (default on POSIX): Use ctime to detect changes. This is the safest option. Not supported on Windows (ctime is file creation time there).

•   mtime (default on Windows): Use mtime to detect changes.

•   disabled: Disable the "file has changed while we backed it up" detection completely. This is not recommended unless you know what you're doing, as it could lead to inconsistent backups if files change during the backup process.

    The mount points of filesystems or filesystem snapshots should be the same for every creation of a new archive to ensure fast operation. This is because the file cache that is used to determine changed files quickly uses absolute filenames. If this is not possible, consider creating a bind mount to a stable location.

    The --progress option shows (from left to right) Original and (uncompressed) deduplicated size (O and U respectively), then the Number of files (N) processed so far, followed by the currently processed path.

    Sizes of GB and above are shown with enough decimal places that even MB-sized progress stays visible. On a terminal, this needs a width of at least 110 columns - on narrower terminals, the compact format is used, so that the path stays readable. If the output does not go to a terminal (e.g. into a logfile), the precise format is always used.

    When using --stats, you will get some statistics about how much data was added - the "This Archive" deduplicated size there is most interesting as that is how much your repository will grow. Please note that the "All archives" stats refer to the state after creation.

    When --stats is used together with --dry-run, only the number of files and the original size are reported. They are computed from file system metadata, without reading the file contents, so a dry run stays fast. As data is not actually read, chunked, and deduplicated during a dry run, the deduplicated size is unknown. The sizes of data read from standard input, from a command's output, or from special files (--read-special) are also unknown in a dry run and counted as zero.

    The --stats output also reports the store statistics (lines prefixed with "Store"), taken from the storage layer after this run. These cover the backend and the local store cache: call counts and timings per operation, the load/store data volumes and throughput, and cache hits/misses. "Store backend load volume" and "Store backend store volume" are the bytes actually read from and sent to the backend; a load counts only what missed the cache, and a store counts chunk data together with Borg's own index and metadata writes. The values are approximate because of write buffering and caching. On a repeated backup a near-zero store volume means almost no new data had to be written, because the chunks already exist in the repository (deduplication).

    The "Added", "Modified" and "Unchanged" file counters come from the files-cache comparison described above: "Unchanged" files matched the cached metadata and were not read again (their existing chunks are reused); "Added" and "Modified" files did not match and were read and chunked (new chunks are stored, already-known chunks are deduplicated). The comparison uses the files cache, keyed by the file's absolute path.

    For more help on include/exclude patterns, see the borg_patterns command output.

    For more help on placeholders, see the borg_placeholders command output.

OPTIONS

See borg-common(1) for common options of Borg commands.

  arguments

NAME
    specify the archive name

PATH
    paths to archive

  options

-n, --dry-run
    do not create a backup archive

-s, --stats
    print statistics for the created archive

--list
    output a verbose list of items (files, dirs, ...)

--filter STATUSCHARS
    only display items with the given status characters (see description)

--json
    output stats as JSON. Implies --stats.

--stdin-name NAME
    use NAME in archive for stdin data (default: 'stdin')

--stdin-user USER
    set user USER in archive for stdin data (default: do not store user/uid)

--stdin-group GROUP
    set group GROUP in archive for stdin data (default: do not store group/gid)

--stdin-mode M
    set mode to M in archive for stdin data (default: 0660)

--content-from-command
    interpret PATH as a command and store its stdout. See also the section 'Reading from stdin' below.

--paths-from-stdin
    read DELIM-separated list of paths to back up from stdin. All control is external: it will back up all files given - no more, no less.

--paths-from-command
    interpret PATH as command and treat its output as --paths-from-stdin

--paths-from-shell-command
    interpret PATH as shell command and treat its output as --paths-from-stdin

--paths-delimiter DELIM
    set path delimiter for --paths-from-stdin and --paths-from-command (default: \n)

  Include/Exclude options

-e PATTERN, --exclude PATTERN
    exclude paths matching PATTERN

--exclude-from EXCLUDEFILE
    read exclude patterns from EXCLUDEFILE, one per line

--pattern PATTERN
    include/exclude paths matching PATTERN

--patterns-from PATTERNFILE
    read include/exclude patterns from PATTERNFILE, one per line

--exclude-caches
    exclude directories that contain a CACHEDIR.TAG file (<https://www.bford.info/cachedir/spec.html>)

--exclude-if-present NAME
    exclude directories that are tagged by containing a filesystem object with the given NAME

--keep-exclude-tags
    if tag objects are specified with --exclude-if-present, do not omit the tag objects themselves from the backup archive

--exclude-dataless
    exclude files flagged DATALESS (macOS: placeholder files whose content is not materialized locally, e.g. not-downloaded cloud storage files)

  Filesystem options

-x, --one-file-system
    stay in the same file system and do not store mount points of other file systems - this might behave different from your expectations, see the description below.

--numeric-ids
    only store numeric user and group identifiers

--atime
    do store atime into archive

--noctime
    do not store ctime into archive

--nobirthtime
    do not store birthtime (creation date) into archive

--noflags
    do not read and store flags (e.g. NODUMP, IMMUTABLE) into archive

--noacls
    do not read and store ACLs into archive

--noxattrs
    do not read and store xattrs into archive

--sparse
    detect sparse holes in input and seek over them instead of reading them

--digests ALGOS
    compute these hash digests over the full content of each file and store them into the archive items. Comma-separated list of hash algorithm names, e.g. "blake3", or "none". default: none

--files-cache MODE
    operate files cache in MODE. default: ctime,size,inode (on Windows: mtime,size,inode, because ctime is file creation time there).

--files-changed MODE
    specify how to detect if a file has changed during backup (ctime, mtime, disabled). default: ctime (on Windows: mtime, because ctime is file creation time there).

--read-special
    open and read block and char device files as well as FIFOs as if they were regular files. Also follows symlinks pointing to these kinds of files.

--read-special-timeout SECONDS
    when reading from FIFOs or character devices (see --read-special): skip the file with an error if no data arrives for more than SECONDS (this includes waiting for a FIFO's writer to connect). Give 0 to wait forever. default: 1800 seconds.

--map MAPFILE
    give a map file describing the content ranges of the (single) input file, so borg does not need to read all of it. See the Input maps section below.

--reuse-from ARCHIVE
    reuse the chunks of this reference archive for the input map's same ranges (requires --map). See the Input maps section below.

--reuse-path PATH
    archive-internal path of the reference item in the --reuse-from archive (only needed if that archive contains more than one file item).

  Archive options

--comment COMMENT
    add a comment text to the archive

--timestamp TIMESTAMP
    manually specify the archive creation date/time (yyyy-mm-ddThh:mm:ss[(+|-)HH:MM] format, (+|-)HH:MM is the UTC offset, default: local time zone). Alternatively, give a reference file/directory.

--chunker-params PARAMS
    specify the chunker parameters (ALGO, CHUNK_MIN_EXP, CHUNK_MAX_EXP, HASH_MASK_BITS, NC_LEVEL). default: fastcdc,19,23,21,2

-C COMPRESSION, --compression COMPRESSION
    select compression algorithm, see the output of the "borg help compression" command for details.

--tags TAG
    add tags to archive (comma-separated or multiple arguments)

EXAMPLES

Note: Archive series and performance: In Borg 2, archives that share the same NAME form an "archive series". The files cache is maintained per series. For best performance on repeated backups, reuse the same NAME every time you run borg create for the same dataset (e.g. always use my-documents). Frequently changing the NAME (for example by embedding date/time like my-documents-2025-11-10) prevents cache reuse and forces Borg to re-scan and re-chunk files, which can make incremental backups vastly slower. Only vary the NAME if you intentionally want to start a new series.

If you must vary the archive name but still want cache reuse across names, see the advanced knobs described in upgradenotes2 (BORG_FILES_CACHE_SUFFIX and BORG_FILES_CACHE_TTL), but the recommended approach is to keep a stable NAME per series.

    # Backup ~/Documents into an archive named "my-documents"
    $ borg create my-documents ~/Documents
    # same, but list all files as we process them
    $ borg create --list my-documents ~/Documents
    # Backup /mnt/disk/docs, but strip path prefix using the slashdot hack
    $ borg create --repo /path/to/repo docs /mnt/disk/./docs
    # Backup ~/Documents and ~/src but exclude pyc files
    $ borg create my-files                \
        ~/Documents                       \
        ~/src                             \
        --exclude '*.pyc'
    # Backup home directories excluding image thumbnails (i.e. only
    # /home/<one directory>/.thumbnails is excluded, not /home/*/*/.thumbnails etc.)
    $ borg create my-files /home --exclude 'sh:home/*/.thumbnails'
    # Back up the root filesystem into an archive named "root-archive"
    # Use zlib compression (good, but slow) — default is LZ4 (fast, low compression ratio)
    $ borg create -C zlib,6 --one-file-system root-archive /
    # Backup into an archive name like FQDN-root
    $ borg create '{fqdn}-root' /
    # Back up a remote host locally ("pull" style) using SSHFS
    $ mkdir sshfs-mount
    $ sshfs root@example.com:/ sshfs-mount
    $ cd sshfs-mount
    $ borg create example.com-root .
    $ cd ..
    $ fusermount -u sshfs-mount
    # Make a big effort in fine-grained deduplication (big chunk management
    # overhead, needs a lot of RAM and disk space; see the formula in the internals docs):
    $ borg create --chunker-params fastcdc,10,23,16,2 small /smallstuff
    # Backup a raw device (must not be active/in use/mounted at that time)
    $ borg create --read-special --chunker-params fixed,4194304 my-sdx /dev/sdX
    # Backup a sparse disk image (must not be active/in use/mounted at that time)
    $ borg create --sparse --chunker-params fixed,4194304 my-disk my-disk.raw
    # No compression (none)
    $ borg create --compression none arch ~
    # Super fast, low compression (lz4, default)
    $ borg create arch ~
    # Less fast, higher compression (zlib, N = 0..9)
    $ borg create --compression zlib,N arch ~
    # Even slower, even higher compression (lzma, N = 0..9)
    $ borg create --compression lzma,N arch ~
    # Only compress compressible data with lzma,N (N = 0..9)
    $ borg create --compression auto,lzma,N arch ~
    # Use the short hostname and username as the archive name
    $ borg create '{hostname}-{user}' ~
    # Back up relative paths by moving into the correct directory first
    $ cd /home/user/Documents
    # The root directory of the archive will be "projectA"
    $ borg create 'daily-projectA' projectA
    # Use external command to determine files to archive
    # Use --paths-from-stdin with find to back up only files less than 1 MB in size
    $ find ~ -size -1000k | borg create --paths-from-stdin small-files-only
    # Use --paths-from-command with find to back up files from only a given user
    $ borg create --paths-from-command joes-files -- find /srv/samba/shared -user joe
    # Use --paths-from-shell-command with find to back up a few files from only a given user -
    # BE VERY CAREFUL AND ONLY USE TRUSTED INPUT FOR THE SHELL COMMAND!
    $ borg create --paths-from-shell-command some-of-joes-files -- "find /srv/samba/shared -user joe | head"
    # Use --paths-from-stdin with --paths-delimiter (for example, for filenames with newlines in them)
    $ find ~ -size -1000k -print0 | borg create \
        --paths-from-stdin \
        --paths-delimiter "\0" \
        smallfiles-handle-newline

NOTES

The --exclude patterns are not like tar. In tar --exclude .bundler/gems will exclude foo/.bundler/gems. In borg it will not, you need to use --exclude '*/.bundler/gems' to get the same effect.

In addition to using --exclude patterns, it is possible to use --exclude-if-present to specify the name of a filesystem object (e.g. a file or folder name) which, when contained within another folder, will prevent the containing folder from being backed up. By default, the containing folder and all of its contents will be omitted from the backup. If, however, you wish to only include the objects specified by --exclude-if-present in your backup, and not include any other contents of the containing folder, this can be enabled through using the --keep-exclude-tags option.

The -x or --one-file-system option excludes directories, that are mountpoints (and everything in them). It detects mountpoints by comparing the device number from the output of stat() of the directory and its parent directory. Specifically, it excludes directories for which stat() reports a device number different from the device number of their parent. In general: be aware that there are directories with device number different from their parent, which the kernel does not consider a mountpoint and also the other way around. Linux examples for this are bind mounts (possibly same device number, but always a mountpoint) and ALL subvolumes of a btrfs (different device number from parent but not necessarily a mountpoint). macOS examples are the apfs mounts of a typical macOS installation. Therefore, when using --one-file-system, you should double-check that the backup works as intended.

  Item flags

--list outputs a list of all files, directories and other file system items it considered (no matter whether they had content changes or not). For each item, it prefixes a single-letter flag that indicates type and/or status of the item.

If you are interested only in a subset of that output, you can give e.g. --filter=AME and it will only show regular files with A, M or E status (see below).

A uppercase character represents the status of a regular file relative to the "files" cache (not relative to the repo -- this is an issue if the files cache is not used). Metadata is stored in any case and for 'A' and 'M' also new data chunks are stored. For 'U' all data chunks refer to already existing chunks.

•   'A' = regular file, added (see also a_status_oddity in the FAQ)

•   'M' = regular file, modified

•   'U' = regular file, unchanged

•   'C' = regular file, it changed while we backed it up

•   'E' = regular file, an error happened while accessing/reading this file

    A lowercase character means a file type other than a regular file, borg usually just stores their metadata:

•   'd' = directory

•   'b' = block device

•   'c' = char device

•   'h' = regular file, hard link (to already seen inodes)

•   's' = symlink

•   'f' = fifo

    Other flags used include:

•   '+' = included, item would be backed up (if not in dry-run mode)

•   '-' = excluded, item would not be / was not backed up

•   'i' = backup data was read from standard input (stdin)

•   '?' = missing status code (if you see this, please file a bug report!)

  Errors and (incomplete) archives

If an error happens during archive creation (e.g. some file could not be read due to a permission error or some other OS error), borg will log a warning or an error (depending on the type of issue) and continue with the next item.

At the end of the backup, if there were any such issues, borg will exit with a non-zero exit code (usually 1 for warnings).

The archive is still saved even if warnings or errors occurred, but it will only contain the data borg was able to read successfully. It is like a checkpoint (see below), but with a user-given name.

You should always check the backup logs and the exit code of the borg command.

  Reading backup data from stdin

There are two methods to read from stdin. Either specify - as path and pipe directly to borg:

    backup-vm --id myvm --stdout | borg create --repo REPO ARCHIVE -

Or use --content-from-command to have Borg manage the execution of the command and piping. If you do so, the first PATH argument is interpreted as command to execute and any further arguments are treated as arguments to the command:

    borg create --content-from-command --repo REPO ARCHIVE -- backup-vm --id myvm --stdout

-- is used to ensure --id and --stdout are not considered arguments to borg but rather backup-vm.

The difference between the two approaches is that piping to borg creates an archive even if the command piping to borg exits with a failure. In this case, one can end up with truncated output being backed up. Using --content-from-command, in contrast, borg is guaranteed to fail without creating an archive should the command fail. The command is considered failed when it returned a non-zero exit code.

Reading from stdin yields just a stream of data without file metadata associated with it, and the files cache is not needed at all. So it is safe to disable it via --files-cache disabled and speed up backup creation a bit.

By default, the content read from stdin is stored in a file called 'stdin'. Use --stdin-name to change the name.

  Input maps

Usually, borg reads the complete input to determine its contents. If you already know the contents of parts of the input from an external source of truth, you can give that information via --map MAPFILE and borg will not read the known parts. The primary use case is backing up snapshots of large block devices (e.g. LVM thin volumes), where the storage layer knows which ranges are in use.

The map file must describe the whole input: one range per line, in the form START LENGTH STATE (byte values, decimal or 0x-prefixed hexadecimal). The ranges must be sorted, non-overlapping and contiguous, starting at offset 0 and covering the exact input size. # starts a comment, empty lines are ignored. STATE is one of:

•   data: the range's contents are read and backed up.

•   zero: the range is known to read as all-zero bytes. borg stores a hole (all-zero range) of that size without reading the range.

•   same: the range is known to be identical to the same range of the input backed up in the --reuse-from REFARCHIVE reference archive (usually: the previous backup of an earlier snapshot of the same device). borg reuses the reference archive's chunks for such ranges without reading them. This state requires --reuse-from.

    The map is trusted: if it is wrong (e.g. a range marked zero actually contains data, or a range marked same actually changed), the archive will not match the input and borg cannot detect that. Independently verify the source producing the maps, and consider doing a periodic full read backup (without --map).

    For LVM thin volume snapshots, maps can be generated from thin_dump / thin_delta XML with the scripts/lvm-thin-map.py converter from the borg sources; its docstring shows the complete workflow.

    --map requires giving exactly one input path, which must be a regular file or (with --read-special) a block device.

    The reference archive must contain exactly one file item; if it contains more, select the reference item with --reuse-path PATH (its archive-internal path). Reference chunks that only partially overlap same ranges are re-read from the input, so any chunker gives correct results - but a fixed block size chunker (e.g. --chunker-params fixed,4194304, same parameters as used for the reference archive) avoids re-reading at the edges of changed ranges and gives stable chunk boundaries across backups.

  Feeding all file paths from externally

Usually, you give a starting path (recursion root) to borg and then borg automatically recurses, finds and backs up all fs objects contained in there (optionally considering include/exclude rules).

If you need more control and you want to give every single fs object path to borg (maybe implementing your own recursion or your own rules), you can use --paths-from-stdin, --paths-from-command or --paths-from-shell-command (with the latter two, borg will fail to create an archive should the command fail).

Borg supports paths with the slashdot hack to strip path prefixes here also. So, be careful not to unintentionally trigger that.

Symlinks given this way are never followed (unlike recursion roots are), they are archived as symlinks.

SEE ALSO

borg-common(1), borg-delete(1), borg-prune(1), borg-check(1), borg-patterns(1), borg-placeholders(1), borg-compression(1), borg-repo-create(1)

Author
The Borg Collective