borg/docs/man/borg-repo-create.1

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.TH "borg-repo-create" "1" "2026-09-27" "" "borg backup tool"
.SH Name
borg-repo-create \- Creates a new, empty repository.
.SH SYNOPSIS
.sp
borg [common options] repo\-create [options]
.SH DESCRIPTION
.sp
This command creates a new, empty repository. A repository is a \fBborgstore\fP store
containing the deduplicated data from zero or more archives.
.sp
Repository creation can be quite slow for some kinds of stores (e.g. for \fBsftp:\fP) \-
this is due to borgstore pre\-creating all directories needed, making usage of the
store faster.
.SS Encryption mode TL;DR
.sp
The encryption mode can only be configured when creating a new repository \- you can
neither configure it on a per\-archive basis nor change the mode of an existing repository.
This example will likely NOT give optimum performance on your machine (performance
tips will come below):
.INDENT 0.0
.INDENT 3.5
.sp
.EX
borg repo\-create \-\-encryption aes256\-ocb \-\-key\-location repokey
.EE
.UNINDENT
.UNINDENT
.sp
Borg will:
.INDENT 0.0
.IP 1. 3
Ask you to come up with a passphrase.
.IP 2. 3
Create a borg key (which contains some random secrets. See \fIkey_files\fP).
.IP 3. 3
Derive a \(dqkey encryption key\(dq from your passphrase
.IP 4. 3
Encrypt and sign the key with the key encryption key
.IP 5. 3
Store the encrypted borg key in the repository (as an object in the \fBkeys/\fP
namespace of the store). This is why it is essential to use a secure passphrase.
.IP 6. 3
Encrypt and sign your backups to prevent anyone from reading or forging them unless they
have the key and know the passphrase. Make sure to keep a backup of
your key \fBoutside\fP the repository \- do not lock yourself out by
\(dqleaving your keys inside your car\(dq (see \fIborg_key_export\fP).
The encryption is done locally \- if you use a remote repository, the remote machine
never sees your passphrase, your unencrypted key or your unencrypted files.
Chunking and ID generation are also based on your key to improve
your privacy.
.IP 7. 3
Use the key when extracting files to decrypt them and to verify that the contents of
the backups have not been accidentally or maliciously altered.
.UNINDENT
.SS Picking a passphrase
.sp
Make sure you use a good passphrase. Not too short, not too simple. The real
encryption / decryption key is encrypted with / locked by your passphrase.
If an attacker gets your key, they cannot unlock and use it without knowing the
passphrase.
.sp
Be careful with special or non\-ASCII characters in your passphrase:
.INDENT 0.0
.IP \(bu 2
Borg processes the passphrase as Unicode (and encodes it as UTF\-8),
so it does not have problems dealing with even the strangest characters.
.IP \(bu 2
BUT: that does not necessarily apply to your OS/VM/keyboard configuration.
.UNINDENT
.sp
So better use a long passphrase made from simple ASCII characters than one that
includes non\-ASCII stuff or characters that are hard or impossible to enter on
a different keyboard layout.
.sp
You can change your passphrase for existing repositories at any time; it will not affect
the encryption/decryption key or other secrets.
.sp
Borg also accepts an empty passphrase. The repository is still encrypted with a random
key then, but that key is not protected: with \fBrepokey\fP storage, anybody who can read
the repository can also unlock the key, which is as good as no encryption at all (with
\fBkeyfile\fP storage, the key is only on your client, so an empty passphrase may be
acceptable if e.g. the client\(aqs disk is encrypted). You can add a passphrase later with
\fBborg key change\-passphrase\fP\&. \fBborg repo\-info\fP shows whether the key has an empty
passphrase.
.SS Choosing a crypto suite
.sp
Depending on your hardware, hashing and crypto performance may vary widely.
The easiest way to find out what is fastest is to run \fBborg benchmark cpu\fP\&.
.sp
\fB\-\-encryption\fP (\fBrequired\fP) selects the mode:
.INDENT 0.0
.IP \(bu 2
\fBaes256\-ocb\fP: AES256 in OCB mode (encryption + authentication).
.IP \(bu 2
\fBchacha20\-poly1305\fP: ChaCha20 + Poly1305 (encryption + authentication).
.IP \(bu 2
\fBauthenticated\-sha256\fP / \fBauthenticated\-blake3\fP: no encryption, but authentication
(tamper detection) using HMAC\-SHA\-256 resp. keyed BLAKE3.
.UNINDENT
.sp
\fB\-\-id\-hash\fP selects the id hash function of the \fBencrypted\fP modes:
.INDENT 0.0
.IP \(bu 2
\fBsha256\fP (default): HMAC\-SHA\-256.
.IP \(bu 2
\fBblake3\fP: BLAKE3. Often faster on CPUs without SHA hardware acceleration.
.UNINDENT
.sp
For the modes that do not encrypt, the hash is not just used for the chunk ids, it also is
what protects your data \- therefore it is part of the mode name there and \fB\-\-id\-hash\fP
does not apply to them.
.sp
\fB\-\-key\-location\fP selects where the key is stored (orthogonal to the crypto suite):
.INDENT 0.0
.IP \(bu 2
\fBrepokey\fP (default): the key is stored in the repository (under \fBkeys/\fP). Pick this
if you want ease\-of\-use and \(dqpassphrase\(dq security is good enough.
.IP \(bu 2
\fBkeyfile\fP: the key is stored in your home directory (in \fB~/.config/borg/keys\fP). Pick
this if you want \(dqpassphrase and having\-the\-key\(dq security.
.UNINDENT
.sp
You can move the key between these locations later with \fBborg key change\-location\fP\&.
This also applies to the \fBauthenticated\-*\fP modes: they do not encrypt your data, but they
still have a key (used for the id hash and the authentication), so \fB\-\-key\-location\fP
selects where that key is stored, just like for the encrypted modes.
.sp
If you do \fBnot\fP want to encrypt the contents of your backups, but still want to detect
malicious tampering, use \fB\-\-encryption authenticated\-sha256\fP (or \fB\-blake3\fP). These
modes are like an encrypted mode minus the data encryption.
To normally work with \fBauthenticated\-*\fP repositories, you will need the passphrase, but
there is an emergency workaround; see \fBBORG_WORKAROUNDS=authenticated_no_key\fP docs.
.SS Repository defaults
.sp
\fB\-\-compression\fP sets the repository\(aqs default compression: the commands that compress
data (\fBborg create\fP, \fBborg recreate\fP, \fBborg import\-tar\fP, \fBborg transfer\fP,
\fBborg repo\-compress\fP) use it if no compression was given via \fB\-\-compression\fP, the
environment or the default config file (\fBdefault.yaml\fP). Without a repository default,
they use lz4. See \fBborg help compression\fP for the compression specs.
.sp
\fB\-\-chunker\-params\fP sets the repository\(aqs default chunker parameters: \fBborg create\fP and
\fBborg import\-tar\fP use them if no chunker parameters were given (in the same ways as above).
\fBborg recreate\fP and \fBborg transfer\fP only rechunk if \fB\-\-chunker\-params\fP is given, with
\fB\-\-chunker\-params default\fP, they rechunk to the repository\(aqs default chunker parameters.
Without a repository default, the built\-in default chunker parameters are used.
.sp
This is useful if several clients back up into the same repository or if some commands are
run manually: they all compress and chunk the same way without having to give these options.
Using the same chunker parameters is important for deduplication.
\fBborg repo\-info\fP shows the defaults.
.sp
The defaults are stored in the repository and protected by the repository key: changing them
(e.g. removing an \fBobfuscate\fP compression) needs the key. The defaults object is always
written, also when no default was given, so removing it is noticed, too: the commands refuse
to run if it is missing or fails the authentication. \fBborg check\fP reports such an object,
\fBborg check \-\-repair\fP replaces it by empty defaults (the built\-in defaults are used then).
.SS Creating a related repository
.sp
You can use \fBborg repo\-create \-\-other\-repo ORIG_REPO ...\fP to create a related repository
that uses the same secret key material as the given other/original repository.
.sp
By default, only the ID key and chunker secret will be the same (these are important
for deduplication) and the AE crypto keys will be newly generated random keys.
.sp
Optionally, if you use \fB\-\-copy\-crypt\-key\fP you can also keep the same crypt_key
(used for authenticated encryption). This might be desired, for example, if you want to have fewer
keys to manage.
.sp
Creating related repositories is useful, for example, if you want to use \fBborg transfer\fP later.
.SS Creating a related repository for data migration from Borg 1.2 or 1.4
.sp
You can use \fBborg repo\-create \-\-other\-repo ORIG_REPO \-\-from\-borg1 ...\fP to create a related
repository that uses the same secret key material as the given other/original repository.
.sp
Then use \fBborg transfer \-\-other\-repo ORIG_REPO \-\-from\-borg1 ...\fP to transfer the archives.
.SH OPTIONS
.sp
See \fIborg\-common(1)\fP for common options of Borg commands.
.SS options
.INDENT 0.0
.TP
.BI \-\-other\-repo \ SRC_REPOSITORY
reuse the key material from the other repository
.TP
.B  \-\-from\-borg1
other repository is Borg 1.x
.TP
.BI \-e \ ENCRYPTION\fR,\fB \ \-\-encryption \ ENCRYPTION
select the mode: \(aqaes256\-ocb\(aq, \(aqchacha20\-poly1305\(aq, \(aqauthenticated\-sha256\(aq or \(aqauthenticated\-blake3\(aq \fB(required)\fP
.TP
.BI \-i \ HASH\fR,\fB \ \-\-id\-hash \ HASH
select the id hash function of the encrypted modes: \(aqsha256\(aq or \(aqblake3\(aq. The \(aqauthenticated\-sha256\(aq and \(aqauthenticated\-blake3\(aq modes name their hash themselves.
.TP
.BI \-\-key\-location \ LOCATION
where to store the key: \(aqrepokey\(aq (in the repository, default) or \(aqkeyfile\(aq (in the local keys directory).
.TP
.BI \-C \ COMPRESSION\fR,\fB \ \-\-compression \ COMPRESSION
set the default compression of the repository, see the output of the \(dqborg help compression\(dq command for details. Default: no repository default (lz4 is used).
.TP
.BI \-\-chunker\-params \ PARAMS
set the default chunker parameters of the repository (same format as for borg create). Default: no repository default (fastcdc,19,23,21,2 is used).
.TP
.B  \-\-copy\-crypt\-key
copy the crypt_key (used for authenticated encryption) from the key of the other repository (default: new random key).
.UNINDENT
.SH EXAMPLES
.INDENT 0.0
.INDENT 3.5
.sp
.EX
# Local repository
$ export BORG_REPO=/path/to/repo
# Recommended AEAD cryptographic modes (key stored in the repository by default)
$ borg repo\-create \-\-encryption=aes256\-ocb
$ borg repo\-create \-\-encryption=chacha20\-poly1305
# No encryption, only authentication (not recommended)
$ borg repo\-create \-\-encryption=authenticated\-sha256

# For the encrypted modes, \-\-encryption (the cipher / AE algorithm) and \-\-id\-hash
# (the id hash function) are chosen independently. \-\-id\-hash defaults to sha256;
# use blake3 if it is faster on your hardware (run \(aqborg benchmark cpu\(aq to find out).
$ borg repo\-create \-\-encryption=aes256\-ocb \-\-id\-hash=blake3
$ borg repo\-create \-\-encryption=chacha20\-poly1305 \-\-id\-hash=blake3

# The \(aqauthenticated\-*\(aq modes name their id hash themselves, so they
# do not take a separate \-\-id\-hash.
$ borg repo\-create \-\-encryption=authenticated\-blake3

# Where the key is stored (\-\-key\-location) is also chosen independently.
# \-\-key\-location defaults to repokey.
# repokey: stores the encrypted key inside the repository
$ borg repo\-create \-\-encryption=aes256\-ocb \-\-key\-location=repokey
# keyfile: stores the encrypted key in the config dir\(aqs keys/ subdir
# (e.g. ~/.config/borg/keys/ on Linux, ~/Library/Application Support/borg/keys/ on macOS)
$ borg repo\-create \-\-encryption=aes256\-ocb \-\-key\-location=keyfile
.EE
.UNINDENT
.UNINDENT
.SH SEE ALSO
.sp
\fIborg\-common(1)\fP, \fIborg\-repo\-delete(1)\fP, \fIborg\-repo\-list(1)\fP, \fIborg\-check(1)\fP, \fIborg\-benchmark\-cpu(1)\fP, \fIborg\-key\-import(1)\fP, \fIborg\-key\-export(1)\fP, \fIborg\-key\-change\-passphrase(1)\fP
.SH Author
The Borg Collective
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