borg-create - Create new archive

Author

       The Borg Collective

                                                   2022-02-19                                     BORG-CREATE(1)

Description

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

When giving '-' as path, borg will read data from standard input and create a file 'stdin' in the created
archive from that data. In some cases it's more appropriate to use --content-from-command, however. See
section Readingfromstdin 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 archive name needs to be unique. It must not end in '.checkpoint' or '.checkpoint.N' (with N being a
number), because these names are used for checkpoints and treated in special ways.

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
weren't 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)

• mtime,size,inode (default behaviour of borg versions older than 1.1.0rc4)

• 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 can not 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.

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, Compressed and Deduplicated (O, C and D,
respectively), then the Number of files (N) processed so far, followed by the currently processed path.

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. Also, the --stats and --dry-run options
are mutually exclusive because the data is not actually compressed and deduplicated during a dry run.

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

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

Examples

          # Backup ~/Documents into an archive named "my-documents"
          $ borg create /path/to/repo::my-documents ~/Documents

          # same, but list all files as we process them
          $ borg create --list /path/to/repo::my-documents ~/Documents

          # Backup ~/Documents and ~/src but exclude pyc files
          $ borg create /path/to/repo::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 /path/to/repo::my-files /home \
              --exclude 'sh:/home/*/.thumbnails'

          # Backup the root filesystem into an archive named "root-YYYY-MM-DD"
          # use zlib compression (good, but slow) - default is lz4 (fast, low compression ratio)
          $ borg create -C zlib,6 --one-file-system /path/to/repo::root-{now:%Y-%m-%d} /

          # Backup onto a remote host ("push" style) via ssh to port 2222,
          # logging in as user "borg" and storing into /path/to/repo
          $ borg create ssh://borg@backup.example.org:2222/path/to/repo::{fqdn}-root-{now} /

          # Backup a remote host locally ("pull" style) using sshfs
          $ mkdir sshfs-mount
          $ sshfs root@example.com:/ sshfs-mount
          $ cd sshfs-mount
          $ borg create /path/to/repo::example.com-root-{now:%Y-%m-%d} .
          $ cd ..
          $ fusermount -u sshfs-mount

          # Make a big effort in fine granular deduplication (big chunk management
          # overhead, needs a lot of RAM and disk space, see formula in internals
          # docs - same parameters as borg < 1.0 or attic):
          $ borg create --chunker-params buzhash,10,23,16,4095 /path/to/repo::small /smallstuff

          # Backup a raw device (must not be active/in use/mounted at that time)
          $ borg create --read-special --chunker-params fixed,4194304 /path/to/repo::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 /path/to/repo::my-disk my-disk.raw

          # No compression (none)
          $ borg create --compression none /path/to/repo::arch ~

          # Super fast, low compression (lz4, default)
          $ borg create /path/to/repo::arch ~

          # Less fast, higher compression (zlib, N = 0..9)
          $ borg create --compression zlib,N /path/to/repo::arch ~

          # Even slower, even higher compression (lzma, N = 0..9)
          $ borg create --compression lzma,N /path/to/repo::arch ~

          # Only compress compressible data with lzma,N (N = 0..9)
          $ borg create --compression auto,lzma,N /path/to/repo::arch ~

          # Use short hostname, user name and current time in archive name
          $ borg create /path/to/repo::{hostname}-{user}-{now} ~
          # Similar, use the same datetime format that is default as of borg 1.1
          $ borg create /path/to/repo::{hostname}-{user}-{now:%Y-%m-%dT%H:%M:%S} ~
          # As above, but add nanoseconds
          $ borg create /path/to/repo::{hostname}-{user}-{now:%Y-%m-%dT%H:%M:%S.%f} ~

          # Backing 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 /path/to/repo::daily-projectA-{now:%Y-%m-%d} projectA

          # Use external command to determine files to archive
          # Use --paths-from-stdin with find to only backup files less than 1MB in size
          $ find ~ -size -1000k | borg create --paths-from-stdin /path/to/repo::small-files-only
          # Use --paths-from-command with find to only backup files from a given user
          $ borg create --paths-from-command /path/to/repo::joes-files -- find /srv/samba/shared -user joe
          # 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" \
              /path/to/repo::smallfiles-handle-newline

Name

       borg-create - Create new archive

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. Be aware that in Linux (and possibly elsewhere) there
are directories with device number different from their parent, which the kernel does not consider a
mountpoint and also the other way around. Examples 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). Therefore when using --one-file-system, one should make doubly sure that the
backup works as intended especially when using btrfs. This is even more important, if the btrfs layout
was created by someone else, e.g. a distribution installer.

Itemflags--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, hardlink (to already seen inodes)

• 's' = symlink

• 'f' = fifo

Other flags used include:

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

• '-' = dry run, item was not backed up

• 'x' = excluded, item was not backed up

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

Readingfromstdin
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::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::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, onecanendupwithtruncatedoutputbeingbackedup.
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-cachedisabled 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.

Options

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

   argumentsARCHIVE
              name of archive to create (must be also a valid directory name)

       PATH   paths to archive

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

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

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

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

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

       --no-cache-sync
              experimental: do not synchronize the cache. Implies not using the files cache.

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

       --stdin-userUSER
              set user USER in archive for stdin data (default: 'root')

       --stdin-groupGROUP
              set group GROUP in archive for stdin data (default: 'wheel')

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

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

       --paths-from-stdin
              read DELIM-separated list of paths to backup from stdin. Will not recurse into directories.

       --paths-from-command
              interpret PATH as command and treat its output as --paths-from-stdin--paths-delimiterDELIM
              set path delimiter for --paths-from-stdin and --paths-from-command (default: n)

   Exclusionoptions-ePATTERN, --excludePATTERN
              exclude paths matching PATTERN

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

       --patternPATTERN
              include/exclude paths matching PATTERN

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

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

       --exclude-if-presentNAME
              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, don't omit the tag objects themselves from
              the backup archive

       --exclude-nodump
              exclude files flagged NODUMP

   Filesystemoptions-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 docs.

       --numeric-owner
              deprecated, use --numeric-ids instead

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

       --noatime
              do not store atime into archive

       --atime
              do store atime into archive

       --noctime
              do not store ctime into archive

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

       --nobsdflags
              deprecated, use --noflags instead

       --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 (supported only by fixed chunker)

       --files-cacheMODE
              operate files cache in MODE. default: ctime,size,inode

       --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.

   Archiveoptions--commentCOMMENT
              add a comment text to the archive

       --timestampTIMESTAMP
              manually  specify the archive creation date/time (UTC, yyyy-mm-ddThh:mm:ss format). Alternatively,
              give a reference file/directory.

       -cSECONDS, --checkpoint-intervalSECONDS
              write checkpoint every SECONDS seconds (Default: 1800)

       --chunker-paramsPARAMS
              specify   the   chunker   parameters   (ALGO,   CHUNK_MIN_EXP,   CHUNK_MAX_EXP,    HASH_MASK_BITS,
              HASH_WINDOW_SIZE). default: buzhash,19,23,21,4095

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

Synopsis

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