oracular (1) borg.1.gz

Provided by: borgbackup2_2.0.0b9-2_amd64 bug

NAME

       borg - deduplicating and encrypting backup tool

SYNOPSIS

       borg [common options] <command> [options] [arguments]

DESCRIPTION

       BorgBackup  (short:  Borg)  is  a  deduplicating backup program.  Optionally, it supports compression and
       authenticated encryption.

       The main goal of Borg is to provide an efficient and secure way to back data up.  The data  deduplication
       technique  used  makes  Borg suitable for daily backups since only changes are stored.  The authenticated
       encryption technique makes it suitable for backups to targets not fully trusted.

       Borg stores a set of files in an archive. A repository  is  a  collection  of  archives.  The  format  of
       repositories  is  Borg-specific. Borg does not distinguish archives from each other in any way other than
       their name, it does not matter when or where archives were created (e.g. different hosts).

EXAMPLES

   A step-by-step example
       1. Before a backup can be made, a repository has to be initialized:

             $ borg -r /path/to/repo rcreate --encryption=repokey-aes-ocb

       2. Back up the ~/src and ~/Documents directories into an archive called Monday:

             $ borg -r /path/to/repo create Monday ~/src ~/Documents

       3. The next day create a new archive called Tuesday:

             $ borg -r /path/to/repo create --stats Tuesday ~/src ~/Documents

          This backup will be a lot quicker and a lot smaller since only new, never before seen data is  stored.
          The  --stats  option  causes  Borg  to  output  statistics about the newly created archive such as the
          deduplicated size (the amount of unique data not shared with other archives):

             Repository: /path/to/repo
             Archive name: Tuesday
             Archive fingerprint: bcd1b53f9b4991b7afc2b339f851b7ffe3c6d030688936fe4552eccc1877718d
             Time (start): Sat, 2022-06-25 20:21:43
             Time (end):   Sat, 2022-06-25 20:21:43
             Duration: 0.07 seconds
             Utilization of max. archive size: 0%
             Number of files: 699
             Original size: 31.14 MB
             Deduplicated size: 502 B

       4. List all archives in the repository:

             $ borg -r /path/to/repo rlist
             Monday                               Sat, 2022-06-25 20:21:14 [b80e24d2...b179f298]
             Tuesday                              Sat, 2022-06-25 20:21:43 [bcd1b53f...1877718d]

       5. List the contents of the Monday archive:

             $ borg -r /path/to/repo list Monday
             drwxr-xr-x user   group          0 Mon, 2016-02-15 18:22:30 home/user/Documents
             -rw-r--r-- user   group       7961 Mon, 2016-02-15 18:22:30 home/user/Documents/Important.doc
             ...

       6. Restore the Monday archive by extracting the files relative to the current directory:

             $ borg -r /path/to/repo extract Monday

       7. Delete the Monday archive (please note that this does not free repo disk space):

             $ borg -r /path/to/repo delete -a Monday

          Please note the -a option here (short for --match-archives) which enables you to  give  a  pattern  to
          delete  multiple archives, like -a 'sh:oldcrap-*'.  You can also combine this with --first, --last and
          --sort-by.  Be careful, always first use with --dry-run and --list!

       8. Recover disk space by compacting the segment files in the repo:

             $ borg -r /path/to/repo compact

       NOTE:
          Borg is quiet by default (it defaults to WARNING log level).  You can use options like  --progress  or
          --list  to  get  specific  reports during command execution.  You can also add the -v (or --verbose or
          --info) option to adjust the log level to INFO to get other informational messages.

NOTES

   Positional Arguments and Options: Order matters
       Borg only supports taking options (-s and --progress in  the  example)  to  the  left  or  right  of  all
       positional arguments (repo::archive and path in the example), but not in between them:

          borg create -s --progress archive path  # good and preferred
          borg create archive path -s --progress  # also works
          borg create -s archive path --progress  # works, but ugly
          borg create archive -s --progress path  # BAD

       This is due to a problem in the argparse module: https://bugs.python.org/issue15112

   Repository URLs
       Local filesystem (or locally mounted network filesystem):

       /path/to/repo - filesystem path to repo directory, absolute path

       path/to/repo - filesystem path to repo directory, relative path

       Also, stuff like ~/path/to/repo or ~other/path/to/repo works (this is expanded by your shell).

       Note: you may also prepend a file:// to a filesystem path to get URL style.

       Remote repositories accessed via ssh user@host:

       ssh://user@host:port/path/to/repo - absolute path`

       ssh://user@host:port/./path/to/repo - path relative to current directory

       ssh://user@host:port/~/path/to/repo - path relative to user's home directory

       If  you frequently need the same repo URL, it is a good idea to set the BORG_REPO environment variable to
       set a default for the repo URL:

          export BORG_REPO='ssh://user@host:port/path/to/repo'

       Then just leave away the --repo option if you want to use the default - it will be  read  from  BORG_REPO
       then.

   Repository Locations / Archive names
       Many  commands  need  to  know  the  repository  location,  give  it via -r / --repo or use the BORG_REPO
       environment variable.

       Commands needing one or two archive names usually get them as positional argument.

       Commands working with an arbitrary amount of archives, usually take -a ARCH_GLOB.

       Archive names must not contain the / (slash) character. For simplicity, maybe also avoid blanks or  other
       characters  that  have  special  meaning on the shell or in a filesystem (borg mount will use the archive
       name as directory name).

   Logging
       Borg writes all log output to stderr by default. But please note that something showing up on stderr does
       not indicate an error condition just because it is on stderr. Please check the log levels of the messages
       and the return code of borg for determining error, warning or success conditions.

       If you want to capture the log output to a file, just redirect it:

          borg create repo::archive myfiles 2>> logfile

       Custom logging configurations can be implemented via BORG_LOGGING_CONF.

       The log level of the builtin logging configuration defaults to WARNING.  This is because we want Borg  to
       be mostly silent and only output warnings, errors and critical messages, unless output has been requested
       by supplying an option that implies output (e.g. --list or --progress).

       Log levels: DEBUG < INFO < WARNING < ERROR < CRITICAL

       Use --debug to set DEBUG log level - to get debug, info, warning, error and critical level output.

       Use --info (or -v or --verbose) to set INFO log level - to get info, warning, error  and  critical  level
       output.

       Use --warning (default) to set WARNING log level - to get warning, error and critical level output.

       Use --error to set ERROR log level - to get error and critical level output.

       Use --critical to set CRITICAL log level - to get critical level output.

       While  you  can  set  misc.  log  levels,  do not expect that every command will give different output on
       different log levels - it's just a possibility.

       WARNING:
          Options --critical and --error are provided for completeness, their usage is not  recommended  as  you
          might miss important information.

   Return codes
       Borg can exit with the following return codes (rc):

                                 ┌────────────┬───────────────────────────────────────┐
                                 │Return code │ Meaning                               │
                                 ├────────────┼───────────────────────────────────────┤
                                 │0           │ success (logged as INFO)              │
                                 ├────────────┼───────────────────────────────────────┤
                                 │1           │ generic  warning  (operation  reached │
                                 │            │ its  normal  end,  but   there   were │
                                 │            │ warnings -- you should check the log, │
                                 │            │ logged as WARNING)                    │
                                 ├────────────┼───────────────────────────────────────┤
                                 │2           │ generic error (like a fatal error,  a │
                                 │            │ local   or   remote   exception,  the │
                                 │            │ operation did not  reach  its  normal │
                                 │            │ end, logged as ERROR)                 │
                                 ├────────────┼───────────────────────────────────────┤
                                 │3..99       │ specific     error     (enabled    by │
                                 │            │ BORG_EXIT_CODES=modern)               │
                                 ├────────────┼───────────────────────────────────────┤
                                 │100..127    │ specific    warning    (enabled    by │
                                 │            │ BORG_EXIT_CODES=modern)               │
                                 └────────────┴───────────────────────────────────────┘

                                 │128+N       │ killed  by signal N (e.g. 137 == kill │
                                 │            │ -9)                                   │
                                 └────────────┴───────────────────────────────────────┘

       If you use --show-rc, the return code is also logged at the indicated level as the last log entry.

   Environment Variables
       Borg uses some environment variables for automation:

       General:

              BORG_REPO
                     When set, use the value to give the default repository location.  Use this so  you  do  not
                     need to type --repo /path/to/my/repo all the time.

              BORG_OTHER_REPO
                     Similar to BORG_REPO, but gives the default for --other-repo.

              BORG_PASSPHRASE
                     When  set,  use the value to answer the passphrase question for encrypted repositories.  It
                     is used when a passphrase is needed to access an encrypted repo  as  well  as  when  a  new
                     passphrase  should  be  initially  set  when  initializing  an  encrypted  repo.   See also
                     BORG_NEW_PASSPHRASE.

              BORG_PASSCOMMAND
                     When set, use the standard output of the command (trailing newlines are stripped) to answer
                     the passphrase question for encrypted repositories.  It is used when a passphrase is needed
                     to access an encrypted repo as well as when a new passphrase should be initially  set  when
                     initializing  an  encrypted  repo.  Note  that  the command is executed without a shell. So
                     variables, like $HOME will work, but ~ won't.  If BORG_PASSPHRASE is  also  set,  it  takes
                     precedence.  See also BORG_NEW_PASSPHRASE.

              BORG_PASSPHRASE_FD
                     When set, specifies a file descriptor to read a passphrase from. Programs starting borg may
                     choose to open an anonymous pipe and use it to  pass  a  passphrase.  This  is  safer  than
                     passing  via  BORG_PASSPHRASE,  because  on  some  systems  (e.g. Linux) environment can be
                     examined by other processes.  If BORG_PASSPHRASE or BORG_PASSCOMMAND  are  also  set,  they
                     take precedence.

              BORG_NEW_PASSPHRASE
                     When  set,  use  the value to answer the passphrase question when a new passphrase is asked
                     for.   This  variable  is  checked  first.  If  it  is   not   set,   BORG_PASSPHRASE   and
                     BORG_PASSCOMMAND  will  also  be  checked.  Main usecase for this is to automate fully borg
                     change-passphrase.

              BORG_DISPLAY_PASSPHRASE
                     When set, use the value to answer the "display the passphrase  for  verification"  question
                     when defining a new passphrase for encrypted repositories.

              BORG_EXIT_CODES
                     When set to "modern", the borg process will return more specific exit codes (rc).  When set
                     to "legacy", the borg process will return rc 2 for all errors, 1 for all  warnings,  0  for
                     success.  Default is "modern".

              BORG_HOST_ID
                     Borg  usually  computes  a  host id from the FQDN plus the results of uuid.getnode() (which
                     usually returns a unique id based on the MAC address of the network  interface.  Except  if
                     that MAC happens to be all-zero - in that case it returns a random value, which is not what
                     we want (because it kills automatic stale lock removal).  So, if you have  a  all-zero  MAC
                     address  or  other  reasons  to  control  better  externally  the  host  id,  just set this
                     environment variable to a unique value. If all your FQDNs are unique, you can just use  the
                     FQDN. If not, use fqdn@uniqueid.

              BORG_LOCK_WAIT
                     You  can  set the default value for the --lock-wait option with this, so you do not need to
                     give it as a commandline option.

              BORG_LOGGING_CONF
                     When set, use the given filename as INI-style logging configuration.  A basic example  conf
                     can be found at docs/misc/logging.conf.

              BORG_RSH
                     When set, use this command instead of ssh. This can be used to specify ssh options, such as
                     a custom identity file ssh -i /path/to/private/key. See man ssh for  other  options.  Using
                     the --rsh CMD commandline option overrides the environment variable.

              BORG_REMOTE_PATH
                     When  set,  use  the  given  path  as  borg executable on the remote (defaults to "borg" if
                     unset).  Using --remote-path PATH commandline option overrides the environment variable.

              BORG_FILES_CACHE_SUFFIX
                     When set to a value at least one character long, instructs borg to use a specifically named
                     (based on the suffix) alternative files cache. This can be used to avoid loading and saving
                     cache entries for backup sources other than the current sources.

              BORG_FILES_CACHE_TTL
                     When set to a numeric value, this determines the maximum "time to live" for the files cache
                     entries  (default:  20).  The  files  cache  is used to determine quickly whether a file is
                     unchanged.  The FAQ explains this more detailed in: always_chunking

              BORG_USE_CHUNKS_ARCHIVE
                     When set to no (default: yes), the chunks.archive.d folder will not be used.  This  reduces
                     disk space usage but slows down cache resyncs.

              BORG_SHOW_SYSINFO
                     When  set  to  no  (default:  yes),  system  information  (like OS, Python version, ...) in
                     exceptions is not shown.  Please only use for good reasons as it  makes  issues  harder  to
                     analyze.

              BORG_FUSE_IMPL
                     Choose  the  lowlevel  FUSE  implementation  borg  shall  use  for  borg  mount.  This is a
                     comma-separated list of implementation names, they are tried in the given order, e.g.:

                     • pyfuse3,llfuse: default, first try to load pyfuse3, then try to load llfuse.

                     • llfuse,pyfuse3: first try to load llfuse, then try to load pyfuse3.

                     • pyfuse3: only try to load pyfuse3

                     • llfuse: only try to load llfuse

                     • none: do not try to load an implementation

              BORG_CACHE_IMPL
                     Choose the implementation for the clientside cache, choose one of:

                     • local: uses a persistent chunks cache and keeps it in a perfect state (precise  refcounts
                       and  sizes),  requiring  a  potentially  resource  expensive  cache  sync in multi-client
                       scenarios.  Also has a persistent files cache.

                     • adhoc: builds a non-persistent chunks cache by querying the repo. Chunks  cache  contents
                       are  somewhat  sloppy for already existing chunks, concerning their refcount ("infinite")
                       and size (0). No files cache (slow, will chunk all input files). DEPRECATED.

                     • adhocwithfiles: Like adhoc, but with a persistent files cache. Default implementation.

                     • cli: Determine the cache implementation from cli options. Without special  options,  will
                       usually end up with the local implementation.

              BORG_SELFTEST
                     This  can  be  used  to  influence borg's builtin self-tests. The default is to execute the
                     tests at the beginning of each borg command invocation.

                     BORG_SELFTEST=disabled can be used to switch off the  tests  and  rather  save  some  time.
                     Disabling  is not recommended for normal borg users, but large scale borg storage providers
                     can use this to optimize production servers after at least doing a one-time test borg (with
                     selftests not disabled) when installing or upgrading machines / OS / borg.

              BORG_WORKAROUNDS
                     A  list  of  comma  separated strings that trigger workarounds in borg, e.g. to work around
                     bugs in other software.

                     Currently known strings are:

                     basesyncfile
                            Use the more simple BaseSyncFile code to avoid  issues  with  sync_file_range.   You
                            might   need  this  to  run  borg  on  WSL  (Windows  Subsystem  for  Linux)  or  in
                            systemd.nspawn containers on some architectures (e.g. ARM).   Using  this  does  not
                            affect  data  safety, but might result in a more bursty write to disk behaviour (not
                            continuously streaming to disk).

                     retry_erofs
                            Retry opening a file without O_NOATIME if  opening  a  file  with  O_NOATIME  caused
                            EROFS.  You  will  need  this  to  make  archives  from volume shadow copies in WSL1
                            (Windows Subsystem for Linux 1).

                     authenticated_no_key
                            Work around a lost passphrase or key for an authenticated mode repository (these are
                            only  authenticated,  but  not  encrypted).  If the key is missing in the repository
                            config, add key = anything there.

                            This workaround is only for emergencies and only to extract data  from  an  affected
                            repository (read-only access):

                               BORG_WORKAROUNDS=authenticated_no_key borg extract repo::archive

                            After you have extracted all data you need, you MUST delete the repository:

                               BORG_WORKAROUNDS=authenticated_no_key borg delete repo

                            Now you can init a fresh repo. Make sure you do not use the workaround any more.

       Output formatting:

              BORG_LIST_FORMAT
                     Giving the default value for borg list --format=X.

              BORG_RLIST_FORMAT
                     Giving the default value for borg rlist --format=X.

              BORG_PRUNE_FORMAT
                     Giving the default value for borg prune --format=X.

       Some automatic "answerers" (if set, they automatically answer confirmation questions):

              BORG_UNKNOWN_UNENCRYPTED_REPO_ACCESS_IS_OK=no (or =yes)
                     For "Warning: Attempting to access a previously unknown unencrypted repository"

              BORG_RELOCATED_REPO_ACCESS_IS_OK=no (or =yes)
                     For "Warning: The repository at location ... was previously located at ..."

              BORG_CHECK_I_KNOW_WHAT_I_AM_DOING=NO (or =YES)
                     For "This is a potentially dangerous function..." (check --repair)

              BORG_DELETE_I_KNOW_WHAT_I_AM_DOING=NO (or =YES)
                     For "You requested to DELETE the repository completely including all archives it contains:"

              Note:  answers  are  case sensitive. setting an invalid answer value might either give the default
              answer or ask you interactively, depending on whether retries are allowed  (they  by  default  are
              allowed). So please test your scripts interactively before making them a non-interactive script.

       Directories and files:

              BORG_BASE_DIR
                     Defaults  to  $HOME  or ~$USER or ~ (in that order).  If you want to move all borg-specific
                     folders to a custom path at once, all you need to do is to modify BORG_BASE_DIR: the  other
                     paths  for  cache,  config  etc.  will adapt accordingly (assuming you didn't set them to a
                     different custom value).

              BORG_CACHE_DIR
                     Defaults to $BORG_BASE_DIR/.cache/borg. If BORG_BASE_DIR is not explicitly  set  while  XDG
                     env  var  XDG_CACHE_HOME  is  set,  then  $XDG_CACHE_HOME/borg is being used instead.  This
                     directory contains the local cache and might need a lot  of  space  for  dealing  with  big
                     repositories.  Make  sure  you're  aware  of  the  associated security aspects of the cache
                     location: cache_security

              BORG_CONFIG_DIR
                     Defaults to $BORG_BASE_DIR/.config/borg. If BORG_BASE_DIR is not explicitly set  while  XDG
                     env  var  XDG_CONFIG_HOME  is  set, then $XDG_CONFIG_HOME/borg is being used instead.  This
                     directory contains all borg configuration directories, see the FAQ for a security  advisory
                     about the data in this directory: home_config_borg

              BORG_DATA_DIR
                     Defaults  to $BORG_BASE_DIR/.local/share/borg. If BORG_BASE_DIR is not explicitly set while
                     XDG env var XDG_DATA_HOME is set, then $XDG_DATA_HOME/borg is  being  used  instead.   This
                     directory contains all borg data directories, see the FAQ for a security advisory about the
                     data in this directory: home_data_borg

              BORG_RUNTIME_DIR
                     Defaults to $BORG_BASE_DIR/.cache/borg. If BORG_BASE_DIR is not explicitly  set  while  XDG
                     env  var  XDG_RUNTIME_DIR  is  set, then $XDG_RUNTIME_DIR/borg is being used instead.  This
                     directory contains borg runtime files, like e.g. the socket file.

              BORG_SECURITY_DIR
                     Defaults to $BORG_DATA_DIR/security.  This directory contains security relevant data.

              BORG_KEYS_DIR
                     Defaults  to  $BORG_CONFIG_DIR/keys.   This   directory   contains   keys   for   encrypted
                     repositories.

              BORG_KEY_FILE
                     When  set,  use  the  given  path as repository key file. Please note that this is only for
                     rather special applications that externally fully manage the key files:

                     • this setting only applies to the keyfile modes (not to the repokey modes).

                     • using a full, absolute path to the key file is recommended.

                     • all directories in the given path must exist.

                     • this setting forces borg to use the key file at the given location.

                     • the key file must either exist (for most commands) or will be created (borg rcreate).

                     • you need to give a different path for different repositories.

                     • you need to point to the correct key  file  matching  the  repository  the  command  will
                       operate on.

              TMPDIR This  is  where  temporary  files  are stored (might need a lot of temporary space for some
                     operations), see tempfile for details.

       Building:

              BORG_OPENSSL_PREFIX
                     Adds given OpenSSL header file directory to the default locations (setup.py).

              BORG_LIBACL_PREFIX
                     Adds given prefix directory to the default locations. If an 'include/acl/libacl.h' is found
                     Borg  will  be  linked  against  the  system  libacl  instead  of a bundled implementation.
                     (setup.py)

              BORG_LIBLZ4_PREFIX
                     Adds given prefix directory to the default locations. If a 'include/lz4.h'  is  found  Borg
                     will be linked against the system liblz4 instead of a bundled implementation. (setup.py)

              BORG_LIBZSTD_PREFIX
                     Adds  given  prefix directory to the default locations. If a 'include/zstd.h' is found Borg
                     will be linked against the system libzstd instead of a bundled implementation. (setup.py)

       Please note:

       • Be very careful when using the "yes" sayers, the warnings with prompt exist  for  your  /  your  data's
         security/safety.

       • Also  be  very  careful  when  putting your passphrase into a script, make sure it has appropriate file
         permissions (e.g.  mode 600, root:root).

   File systems
       We strongly recommend against using Borg (or any other database-like  software)  on  non-journaling  file
       systems  like  FAT,  since  it  is not possible to assume any consistency in case of power failures (or a
       sudden disconnect of an external drive or similar failures).

       While Borg uses a data store that is resilient against  these  failures  when  used  on  journaling  file
       systems,  it is not possible to guarantee this with some hardware -- independent of the software used. We
       don't know a list of affected hardware.

       If you are suspicious whether your Borg repository is still consistent and  readable  after  one  of  the
       failures  mentioned  above  occurred,  run  borg  check  --verify-data  to  make  sure  it is consistent.
       Requirements for Borg repository file systems

       • Long file names

       • At least three directory levels with short names

       • Typically, file sizes up to a few hundred MB.  Large repositories may require large files (>2 GB).

       • Up to 1000 files per directory.

       • rename(2) / MoveFile(Ex) should work as specified, i.e. on the same file system it  should  be  a  move
         (not  a copy) operation, and in case of a directory it should fail if the destination exists and is not
         an empty directory, since this is used for locking.

       • Also hardlinks are used for more safe and secure file updating (e.g. of the repo config file), but  the
         code tries to work also if hardlinks are not supported.

   Units
       To  display  quantities,  Borg  takes  care  of respecting the usual conventions of scale. Disk sizes are
       displayed in decimal, using powers of ten (so kB means 1000 bytes). For memory usage, binary prefixes are
       used, and are indicated using the IEC binary prefixes, using powers of two (so KiB means 1024 bytes).

   Date and Time
       We format date and time conforming to ISO-8601, that is: YYYY-MM-DD and HH:MM:SS (24h clock).

       For more information about that, see: https://xkcd.com/1179/

       Unless  otherwise  noted, we display local date and time.  Internally, we store and process date and time
       as UTC.

   Resource Usage
       Borg might use a lot of resources depending on the size of the data set it is dealing with.

       If one uses Borg in a client/server way (with a ssh: repository), the resource usage occurs  in  part  on
       the client and in another part on the server.

       If  one uses Borg as a single process (with a filesystem repo), all the resource usage occurs in that one
       process, so just add up client + server to get the approximate resource usage.

       CPU client:borg create: does chunking, hashing, compression, crypto (high CPU usage)

              • chunks cache sync: quite heavy on CPU, doing lots of hashtable operations.

              • borg extract: crypto, decompression (medium to high CPU usage)

              • borg check: similar to extract, but depends on options given.

              • borg prune / borg delete archive: low to medium CPU usage

              • borg delete repo: done on the server

              It won't go beyond 100% of 1 core as the code is  currently  single-threaded.   Especially  higher
              zlib  and  lzma compression levels use significant amounts of CPU cycles. Crypto might be cheap on
              the CPU (if hardware accelerated) or expensive (if not).

       CPU server:
              It usually doesn't need much CPU, it just deals with the key/value store (repository) and uses the
              repository index for that.

              borg  check:  the  repository  check  computes the checksums of all chunks (medium CPU usage) borg
              delete repo: low CPU usage

       CPU (only for client/server operation):
              When using borg in a client/server way with a ssh:-type repo,  the  ssh  processes  used  for  the
              transport  layer  will  need  some  CPU on the client and on the server due to the crypto they are
              doing - esp. if you are pumping big amounts of data.

       Memory (RAM) client:
              The chunks index and the files index are read into memory for performance reasons. Might need  big
              amounts  of  memory  (see  below).  Compression, esp. lzma compression with high levels might need
              substantial amounts of memory.

       Memory (RAM) server:
              The server process will load the repository index into memory. Might need considerable amounts  of
              memory, but less than on the client (see below).

       Chunks index (client only):
              Proportional  to  the  amount of data chunks in your repo. Lots of chunks in your repo imply a big
              chunks index.  It is possible to tweak the chunker params (see create options).

       Files index (client only):
              Proportional to the amount of files in  your  last  backups.  Can  be  switched  off  (see  create
              options),  but  next  backup might be much slower if you do.  The speed benefit of using the files
              cache is proportional to file size.

       Repository index (server only):
              Proportional to the amount of data chunks in your repo. Lots of chunks in your repo  imply  a  big
              repository  index.   It  is possible to tweak the chunker params (see create options) to influence
              the amount of chunks being created.

       Temporary files (client):
              Reading data and metadata from a FUSE mounted repository will  consume  up  to  the  size  of  all
              deduplicated, small chunks in the repository. Big chunks won't be locally cached.

       Temporary files (server):
              A  non-trivial  amount  of  data  will be stored on the remote temp directory for each client that
              connects to it. For some remotes, this can fill the default temporary directory at /tmp. This  can
              be remediated by ensuring the $TMPDIR, $TEMP, or $TMP environment variable is properly set for the
              sshd process.  For some OSes, this can be done just by setting the correct value  in  the  .bashrc
              (or  equivalent login config file for other shells), however in other cases it may be necessary to
              first   enable   PermitUserEnvironment    yes    in    your    sshd_config    file,    then    add
              environment="TMPDIR=/my/big/tmpdir"   at   the  start  of  the  public  key  to  be  used  in  the
              authorized_hosts file.

       Cache files (client only):
              Contains the chunks index and files index (plus a collection  of  single-  archive  chunk  indexes
              which  might  need huge amounts of disk space, depending on archive count and size - see FAQ about
              how to reduce).

       Network (only for client/server operation):
              If your repository is remote, all deduplicated (and  optionally  compressed/  encrypted)  data  of
              course  has  to  go  over  the connection (ssh:// repo url).  If you use a locally mounted network
              filesystem, additionally some copy operations used  for  transaction  support  also  go  over  the
              connection.  If  you back up multiple sources to one target repository, additional traffic happens
              for cache resynchronization.

   Support for file metadata
       Besides regular file and directory structures, Borg can preserve

       • symlinks (stored as symlink, the symlink is not followed)

       • special files:

         • character and block device files (restored via mknod)

         • FIFOs ("named pipes")

         • special file contents can be backed up in --read-special mode.  By default  the  metadata  to  create
           them with mknod(2), mkfifo(2) etc. is stored.

       • hardlinked regular files, devices, symlinks, FIFOs (considering all items in the same archive)

       • timestamps in nanosecond precision: mtime, atime, ctime

       • other timestamps: birthtime (on platforms supporting it)

       • permissions:

         • IDs of owning user and owning group

         • names of owning user and owning group (if the IDs can be resolved)

         • Unix Mode/Permissions (u/g/o permissions, suid, sgid, sticky)

       On some platforms additional features are supported:

                              ┌───────────────────────┬──────────┬───────────┬───────────┐
                              │Platform               │ ACLs [5] │ xattr [6] │ Flags [7] │
                              ├───────────────────────┼──────────┼───────────┼───────────┤
                              │Linux                  │ Yes      │ Yes       │ Yes [1]   │
                              ├───────────────────────┼──────────┼───────────┼───────────┤
                              │macOS                  │ Yes      │ Yes       │ Yes (all) │
                              ├───────────────────────┼──────────┼───────────┼───────────┤
                              │FreeBSD                │ Yes      │ Yes       │ Yes (all) │
                              ├───────────────────────┼──────────┼───────────┼───────────┤
                              │OpenBSD                │ n/a      │ n/a       │ Yes (all) │
                              ├───────────────────────┼──────────┼───────────┼───────────┤
                              │NetBSD                 │ n/a      │ No [2]    │ Yes (all) │
                              ├───────────────────────┼──────────┼───────────┼───────────┤
                              │Solaris            and │ No [3]   │ No [3]    │ n/a       │
                              │derivatives            │          │           │           │
                              ├───────────────────────┼──────────┼───────────┼───────────┤
                              │Windows (cygwin)       │ No [4]   │ No        │ No        │
                              └───────────────────────┴──────────┴───────────┴───────────┘

       Other Unix-like operating systems may work as well, but have not been tested at all.

       Note that most of the platform-dependent features also depend on the file system.  For  example,  ntfs-3g
       on Linux isn't able to convey NTFS ACLs.

       [1]  Only  "nodump", "immutable", "compressed" and "append" are supported.  Feature request #618 for more
            flags.

       [2]  Feature request #1332

       [3]  Feature request #1337

       [4]  Cygwin tries to map NTFS ACLs to permissions with varying degrees of success.

       [5]  The native access control list mechanism of the OS. This normally limits access to non-native  ACLs.
            For example, NTFS ACLs aren't completely accessible on Linux with ntfs-3g.

       [6]  extended  attributes;  key-value  pairs  attached  to  a file, mainly used by the OS.  This includes
            resource forks on Mac OS X.

       [7]  aka BSD flags. The Linux set of flags [1] is portable across platforms.  The BSDs define  additional
            flags.

SEE ALSO

       borg-common(1) for common command line options

       borg-rcreate(1),    borg-rdelete(1),   borg-rlist(1),   borg-rinfo(1),   borg-create(1),   borg-mount(1),
       borg-extract(1),   borg-list(1),   borg-info(1),    borg-delete(1),    borg-prune(1),    borg-compact(1),
       borg-recreate(1)

       borg-compression(1), borg-patterns(1), borg-placeholders(1)

       • Main web site https://www.borgbackup.org/

       • Releases https://github.com/borgbackup/borg/releases

       • Changelog https://github.com/borgbackup/borg/blob/master/docs/changes.rst

       • GitHub https://github.com/borgbackup/borg

       • Security contact https://borgbackup.readthedocs.io/en/latest/support.html#security-contact

AUTHOR

       The Borg Collective

       orphan:

                                                   2024-07-22                                            BORG(1)