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DUPLICITY

Section: User Manuals (1)
Updated: February 29, 2012
Index Return to Main Contents

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NAME

duplicity - Encrypted backup using rsync algorithm

 

SYNOPSIS

duplicity [options] source_directory target_url

duplicity [options] source_url target_directory

duplicity full [options] source_directory target_url

duplicity incremental [options] source_directory target_url

duplicity restore [options] source_url target_directory

duplicity verify [options] source_url target_directory

duplicity collection-status [options] target_url

duplicity list-current-files [options] target_url

duplicity cleanup [options] [--force] target_url

duplicity remove-older-than time [options] [--force] target_url

duplicity remove-all-but-n-full count [options] [--force] target_url

duplicity remove-all-inc-of-but-n-full count [options] [--force] target_url

 

DESCRIPTION

Duplicity incrementally backs up files and directory by encrypting tar-format volumes with GnuPG and uploading them to a remote (or local) file server. Currently local, ftp, sftp/scp, rsync, WebDAV, WebDAVs, Google Docs, HSi and Amazon S3 backends are available. Because duplicity uses librsync, the incremental archives are space efficient and only record the parts of files that have changed since the last backup. Currently duplicity supports deleted files, full Unix permissions, directories, symbolic links, fifos, etc., but not hard links.

If you are backing up the root directory /, remember to --exclude /proc, or else duplicity will probably crash on the weird stuff in there.

 

EXAMPLES

Here is an example of a backup, using scp to back up /home/me to some_dir on the other.host machine:

duplicity /home/me scp://uid@other.host/some_dir

If the above is run repeatedly, the first will be a full backup, and subsequent ones will be incremental. To force a full backup, use the full action:

duplicity full /home/me scp://uid@other.host/some_dir

Now suppose we accidentally delete /home/me and want to restore it the way it was at the time of last backup:

duplicity scp://uid@other.host/some_dir /home/me

Duplicity enters restore mode because the URL comes before the local directory. If we wanted to restore just the file "Mail/article" in /home/me as it was three days ago into /home/me/restored_file:

duplicity -t 3D --file-to-restore Mail/article scp://uid@other.host/some_dir /home/me/restored_file

The following command compares the files we backed up, so see what has changed since then:

duplicity verify scp://uid@other.host/some_dir /home/me

Finally, duplicity recognizes several include/exclude options. For instance, the following will backup the root directory, but exclude /mnt, /tmp, and /proc:

duplicity --exclude /mnt --exclude /tmp --exclude /proc / file:///usr/local/backup

Note that in this case the destination is the local directory /usr/local/backup. The following will backup only the /home and /etc directories under root:

duplicity --include /home --include /etc --exclude '**' / file:///usr/local/backup

Duplicity can also access a repository via ftp. If a user name is given, the environment variable FTP_PASSWORD is read to determine the password:

FTP_PASSWORD=mypassword duplicity /local/dir ftp://user@other.host/some_dir

 

ACTIONS

cleanup

Delete the extraneous duplicity files on the given backend. Non-duplicity files, or files in complete data sets will not be deleted. This should only be necessary after a duplicity session fails or is aborted prematurely. Note that --force will be needed to delete the files rather than just list them.

collection-status

Summarize the status of the backup repository by printing the chains and sets found, and the number of volumes in each.

full

Indicate full backup. If this is set, perform full backup even if signatures are available.

incr

If this is requested an incremental backup will be performed. Duplicity will abort if old signatures cannot be found. The default is to switch to full backup under these conditions.

list-current-files

Lists the files currently backed up in the archive. The information will be extracted from the signature files, not the archive data itself. Thus the whole archive does not have to be downloaded, but on the other hand if the archive has been deleted or corrupted, this command may not detect it.

Note: the Debian version of duplicity automatically runs a cleanup --extra-clean whenever old backup sets are removed (i.e. if one of the remove commands is run with the --force option present and if something removable is found). This is to limit the amount of old outdated material that otherwise accumulates in the archive dir.

remove-older-than time

Delete all backup sets older than the given time. Old backup sets will not be deleted if backup sets newer than time depend on them. See the TIME FORMATS section for more information. Note, this action cannot be combined with backup or other actions, such as cleanup. Note also that --force will be needed to delete the files rather than just list them.

remove-all-but-n-full count

Delete all backups sets that are older than the count:th last full backup (in other words, keep the last count full backups and associated incremental sets). count must be larger than zero. A value of 1 means that only the single most recent backup chain will be kept. Note that --force will be needed to delete the files rather than just list them.

remove-all-inc-of-but-n-full count

Delete incremental sets of all backups sets that are older than the count:th last full backup (in other words, keep only old full backups and not their increments). count must be larger than zero. A value of 1 means that only the single most recent backup chain will be kept intact. Note that --force will be needed to delete the files rather than just list them.

The note regarding automatic cleanups above also applies to remove-all-but-n-full.

verify

Enter verify mode instead of restore. If the --file-to-restore option is given, restrict verify to that file or directory. duplicity will exit with a non-zero error level if any files are different. On verbosity level 4 or higher, log a message for each file that has changed.

 

OPTIONS

--allow-source-mismatch

Do not abort on attempts to use the same archive dir or remote backend to back up different directories. duplicity will tell you if you need this switch.

--archive-dir path

The archive directory. NOTE: This option changed in 0.6.0. The archive directory is now necessary in order to manage persistence for current and future enhancements. As such, this option is now used only to change the location of the archive directory. The archive directory should not be deleted, or duplicity will have to recreate it from the remote repository (which may require decrypting the backup contents).

When backing up or restoring, this option specifies that the local archive directory is to be created in path. If the archive directory is not specified, the default will be to create the archive directory in ~/.cache/duplicity/.

The archive directory can be shared between backups to multiple targets, because a subdirectory of the archive dir is used for individual backups (see --name ).

The combination of archive directory and backup name must be unique in order to separate the data of different backups.

The interaction between the --archive-dir and the --name options allows for four possible combinations for the location of the archive dir:

1.

neither specified (default)
 ~/.cache/duplicity/hash-of-url

2.

--archive-dir=/arch, no --name
 /arch/hash-of-url

3.

no --archive-dir, --name=foo
 ~/.cache/duplicity/foo

4.

--archive-dir=/arch, --name=foo
 /arch/foo

--asynchronous-upload

(EXPERIMENTAL) Perform file uploads asynchronously in the background, with respect to volume creation. This means that duplicity can upload a volume while, at the same time, preparing the next volume for upload. The intended end-result is a faster backup, because the local CPU and your bandwidth can be more consistently utilized. Use of this option implies additional need for disk space in the temporary storage location; rather than needing to store only one volume at a time, enough storage space is required to store two volumes.

--dry-run

Calculate what would be done, but do not perform any backend actions

--encrypt-key key

When backing up, encrypt to the given public key, instead of using symmetric (traditional) encryption. Can be specified multiple times.

--encrypt-secret-keyring filename

This option can only be used with --encrypt-key, and changes the path to the secret keyring for the encrypt key to filename This keyring is not used when creating a backup. If not specified, the default secret keyring is used which is usually located at .gnupg/secring.gpg

--encrypt-sign-key key

Convenience parameter. Same as --encrypt-key key --sign-key key.

--exclude shell_pattern

Exclude the file or files matched by shell_pattern. If a directory is matched, then files under that directory will also be matched. See the FILE SELECTION section for more information.

--exclude-device-files

Exclude all device files. This can be useful for security/permissions reasons or if rdiff-backup is not handling device files correctly.

--exclude-filelist filename

Excludes the files listed in filename. See the FILE SELECTION section for more information.

--exclude-filelist-stdin

Like --exclude-filelist, but the list of files will be read from standard input. See the FILE SELECTION section for more information.

--exclude-globbing-filelist filename

Like --exclude-filelist but each line of the filelist will be interpreted according to the same rules as --include and --exclude.

--exclude-if-present filename

Exclude directories if filename is present. This option needs to come before any other include or exclude options.

--exclude-other-filesystems

Exclude files on file systems (identified by device number) other than the file system the root of the source directory is on.

--exclude-regexp regexp

Exclude files matching the given regexp. Unlike the --exclude option, this option does not match files in a directory it matches. See the FILE SELECTION section for more information.

--extra-clean

When cleaning up, be more aggressive about saving space. For example, this may delete signature files for old backup chains. See the cleanup argument for more information.

--file-to-restore path

This option may be given in restore mode, causing only path to be restored instead of the entire contents of the backup archive. path should be given relative to the root of the directory backed up.

--full-if-older-than time

Perform a full backup if an incremental backup is requested, but the latest full backup in the collection is older than the given time. See the TIME FORMATS section for more information.

--force

Proceed even if data loss might result. Duplicity will let the user know when this option is required.

--ftp-passive

Use passive (PASV) data connections. The default is to use passive, but to fallback to regular if the passive connection fails or times out.

--ftp-regular

Use regular (PORT) data connections.

--gio

Use the GIO backend and interpret any URLs as GIO would.

--ignore-errors

Try to ignore certain errors if they happen. This option is only intended to allow the restoration of a backup in the face of certain problems that would otherwise cause the backup to fail. It is not ever recommended to use this option unless you have a situation where you are trying to restore from backup and it is failing because of an issue which you want duplicity to ignore. Even then, depending on the issue, this option may not have an effect.

Please note that while ignored errors will be logged, there will be no summary at the end of the operation to tell you what was ignored, if anything. If this is used for emergency restoration of data, it is recommended that you run the backup in such a way that you can revisit the backup log (look for lines containing the string IGNORED_ERROR).

If you ever have to use this option for reasons that are not understood or understood but not your own responsibility, please contact duplicity maintainers. The need to use this option under production circumstances would normally be considered a bug.

--imap-mailbox option

Allows you to specify a different mailbox. The default is "INBOX". Other languages may require a different mailbox than the default.

--gpg-options options

Allows you to pass options to gpg encryption. The options list should be of the form "opt1=parm1 opt2=parm2" where the string is quoted and the only spaces allowed are between options.

--include shell_pattern

Similar to --exclude but include matched files instead. Unlike --exclude, this option will also match parent directories of matched files (although not necessarily their contents). See the FILE SELECTION section for more information.

--include-filelist filename

Like --exclude-filelist, but include the listed files instead. See the FILE SELECTION section for more information.

--include-filelist-stdin

Like --include-filelist, but read the list of included files from standard input.

--include-globbing-filelist filename

Like --include-filelist but each line of the filelist will be interpreted according to the same rules as --include and --exclude.

--include-regexp regexp

Include files matching the regular expression regexp. Only files explicitly matched by regexp will be included by this option. See the FILE SELECTION section for more information.

--log-fd number

Write specially-formatted versions of output messages to the specified file descriptor. The format used is designed to be easily consumable by other programs.

--log-file filename

Write specially-formatted versions of output messages to the specified file. The format used is designed to be easily consumable by other programs.

--name symbolicname

Set the symbolic name of the backup being operated on. The intent is to use a separate name for each logically distinct backup. For example, someone may use "home_daily_s3" for the daily backup of a home directory to Amazon S3. The structure of the name is up to the user, it is only important that the names be distinct. The symbolic name is currently only used to affect the expansion of --archive-dir , but may be used for additional features in the future. Users running more than one distinct backup are encouraged to use this option.

If not specified, the default value is a hash of the backend URL.

--no-encryption

Do not use GnuPG to encrypt files on remote system. Instead just write gzipped volumes.

--no-print-statistics

By default duplicity will print statistics about the current session after a successful backup. This switch disables that behavior.

--null-separator

Use nulls (\0) instead of newlines (\n) as line separators, which may help when dealing with filenames containing newlines. This affects the expected format of the files specified by the --{include|exclude}-filelist[-stdin] switches as well as the format of the directory statistics file.

--numeric-owner

On restore always use the numeric uid/gid from the archive and not the archived user/group names, which is the default behaviour. Recommended for restoring from live cds which might have the users with identical names but different uids/gids.

--num-retries number

Number of retries to make on errors before giving up.

--old-filenames

Use the old filename format (incompatible with Windows/Samba) rather than the new filename format.

--rename orig new

Treats the path orig in the backup as if it were the path new. Can be passed multiple times. An example:

duplicity restore --rename Documents/metal Music/metal scp://uid@other.host/some_dir /home/me

--rsync-options options

Allows you to pass options to the rsync backend. The options list should be of the form "opt1=parm1 opt2=parm2" where the option string is quoted and the only spaces allowed are between options. The option string will be passed verbatim to rsync, after any internally generated option designating the remote port to use. Here is a possibly useful example:

duplicity --rsync-options="--partial-dir=.rsync-partial" /home/me scp://uid@other.host/some_dir

--s3-european-buckets

When using the Amazon S3 backend, create buckets in Europe instead of the default (requires --s3-use-new-style ). Also see the EUROPEAN S3 BUCKETS section.

--s3-unencrypted-connection

Don't use SSL for connections to S3.

This may be much faster, at some cost to confidentiality.

With this option, anyone who can observe traffic between your computer and S3 will be able to tell: that you are using Duplicity, the name of the bucket, your AWS Access Key ID, the increment dates and the amount of data in each increment.

This option affects only the connection, not the GPG encryption of the backup increment files. Unless that is disabled, an observer will not be able to see the file names or contents.

--s3-use-new-style

When operating on Amazon S3 buckets, use new-style subdomain bucket addressing. This is now the preferred method to access Amazon S3, but is not backwards compatible if your bucket name contains upper-case characters or other characters that are not valid in a hostname.

--scp-command command

Deprecated and ignored. The sftp/scp backend does no longer use an external scp client program.

--sftp-command command

Deprecated and ignored. The sftp/scp backend does no longer use an external sftp client program.

--sign-key key

This option can be used when backing up, restoring or verifying. When backing up, all backup files will be signed with keyid key. When restoring, duplicity will signal an error if any remote file is not signed with the given keyid. key should be an 8 character hex string, like AA0E73D2. Should be specified only once because currently only one signing key is supported. Last entry overrides all other entries.
see also A NOTE ON SYMMETRIC ENCRYPTION AND SIGNING

--ssh-askpass

Tells the sftp/scp backend to use FTP_PASSWORD from the environment, or, if that is not present, to prompt the user for the remote system password. This password is also used for ssh keys that are passphrase-protected. Without this option the password is expected in the url.

--ssh-options options

Allows you to pass options to the ssh/scp/sftp backend. The options list should be of the form "-oopt1=parm1 -oopt2=parm2" where the option string is quoted and the only spaces allowed are between options. Options must be given in the long option format described in ssh_config(5). The sftp/scp backend currently supports only one ssh option, IdentityFile like in this example:

duplicity --ssh-options="-oIdentityFile=/my/backup/id" /home/me sftp://uid@other.host/some_dir

--short-filenames

If this option is specified, the names of the files duplicity writes will be shorter (about 30 chars) but less understandable. This may be useful when backing up to MacOS or another OS or FS that doesn't support long filenames.

--tempdir directory

Use this existing directory for duplicity temporary files instead of the system default, which is usually the /tmp directory. This option supersedes any environment variable.

-ttime, --time time, --restore-time time

Specify the time from which to restore or list files.

--time-separator char

Use char as the time separator in filenames instead of colon (":").

--timeout seconds

Use seconds as the socket timeout value if duplicity begins to timeout during network operations. The default is 30 seconds.

--use-agent

If this option is specified, then --use-agent is passed to the GnuPG encryption process and it will try to connect to gpg-agent before it asks for a passphrase for --encrypt-key or --sign-key if needed.
Note: GnuPG 2 and newer ignore this option and will always use a running gpg-agent if no passphrase was delivered.

--use-scp

If this option is specified, then the sftp/scp backend will use the scp protocol rather than sftp for backend operations. The default is to use sftp, because it does not suffer from shell quoting issues like scp.

--verbosity level, -vlevel

Specify output verbosity level (log level). Named levels and corresponding values are 0 Error, 2 Warning, 4 Notice (default), 8 Info, 9 Debug (noisiest).
level may also be
a character: e, w, n, i, d
a word: error, warning, notice, info, debug

The options -v4, -vn and -vnotice are functionally equivalent, as are the mixed/upper-case versions -vN, -vNotice and -vNOTICE.

--version

Print duplicity's version and quit.

--volsize number

Change the volume size to number Mb. Default is 25Mb.

 

ENVIRONMENT VARIABLES

TMPDIR, TEMP, TMP

In decreasing order of importance, specifies the directory to use for temporary files (inherited from Python's tempfile module).

FTP_PASSWORD

Supported by most backends which are password capable. More secure than setting it in the backend url (which might be readable in the operating systems process listing to other users on the same machine).

PASSPHRASE

This passphrase is passed to GnuPG. If this is not set, the user will be prompted for the passphrase.

SIGN_PASSPHRASE

The passphrase to be used for --sign-key , if SIGN_PASSPHRASE is not set but PASSPHRASE is set, the latter will be used. Otherwise, if no passphrase is available, the user will be prompted for it.

 

URL FORMAT

Duplicity tries to maintain a standard URL format as much as possible. The generic format for a URL is:

scheme://user[:password]@host[:port]/[/]path

It is not recommended to expose the password on the command line since it could be revealed to anyone with permissions to do process listings, however, it is permitted. Consider setting the environment variable FTP_PASSWORD instead, which is supported by most, but not all backends. Regardless of its name it can be used with other backends.

In protocols that support it, the path may be preceded by a single slash, '/path', to represent a relative path to the target home directory, or preceded by a double slash, '//path', to represent an absolute filesystem path.

Formats of each of the URL schemes follow:

cf+http://container_name

file:///some_dir

ftp[s]://user[:password]@other.host[:port]/some_dir

hsi://user[:password]@other.host/some_dir

imap[s]://user[:password]@host.com[/from_address_prefix]
see also A NOTE ON IMAP

using rsync daemon
rsync://user[:password]@host.com[:port]::[/]module/some_dir

using rsync over ssh (only key auth)
rsync://user@host.com[:port]/relative_path
rsync://user@host.com[:port]//absolute_path

s3://host/bucket_name[/prefix]
s3+http://bucket_name[/prefix]
see also A NOTE ON EUROPEAN S3 BUCKETS

Ubuntu One
u1://host/volume_path
u1+http://volume_path
see also A NOTE ON UBUNTU ONE

scp://.. or ssh://.. are synonymous with
sftp://user[:password]@other.host[:port]/[/]some_dir
see also --use-scp

tahoe://alias/directory

webdav[s]://user[:password]@other.host/some_dir

gdocs://user[:password]@other.host/some_dir

 

TIME FORMATS

duplicity uses time strings in two places. Firstly, many of the files duplicity creates will have the time in their filenames in the w3 datetime format as described in a w3 note at http://www.w3.org/TR/NOTE-datetime. Basically they look like "2001-07-15T04:09:38-07:00", which means what it looks like. The "-07:00" section means the time zone is 7 hours behind UTC.

Secondly, the -t, --time, and --restore-time options take a time string, which can be given in any of several formats:

1.

the string "now" (refers to the current time)

2.

a sequences of digits, like "123456890" (indicating the time in seconds after the epoch)

3.

A string like "2002-01-25T07:00:00+02:00" in datetime format

4.

An interval, which is a number followed by one of the characters s, m, h, D, W, M, or Y (indicating seconds, minutes, hours, days, weeks, months, or years respectively), or a series of such pairs. In this case the string refers to the time that preceded the current time by the length of the interval. For instance, "1h78m" indicates the time that was one hour and 78 minutes ago. The calendar here is unsophisticated: a month is always 30 days, a year is always 365 days, and a day is always 86400 seconds.

5.

A date format of the form YYYY/MM/DD, YYYY-MM-DD, MM/DD/YYYY, or MM-DD-YYYY, which indicates midnight on the day in question, relative to the current time zone settings. For instance, "2002/3/5", "03-05-2002", and "2002-3-05" all mean March 5th, 2002.

 

FILE SELECTION

duplicity accepts the same file selection options rdiff-backup does, including --exclude, --exclude-filelist-stdin, etc.

When duplicity is run, it searches through the given source directory and backs up all the files specified by the file selection system. The file selection system comprises a number of file selection conditions, which are set using one of the following command line options: --exclude, --exclude-device-files, --exclude-filelist, --exclude-filelist-stdin, --exclude-globbing-filelist, --exclude-regexp, --include, --include-filelist, --include-filelist-stdin, --include-globbing-filelist, and --include-regexp. Each file selection condition either matches or doesn't match a given file. A given file is excluded by the file selection system exactly when the first matching file selection condition specifies that the file be excluded; otherwise the file is included.

For instance,

duplicity --include /usr --exclude /usr /usr scp://user@host/backup

is exactly the same as

duplicity /usr scp://user@host/backup

because the include and exclude directives match exactly the same files, and the --include comes first, giving it precedence. Similarly,

duplicity --include /usr/local/bin --exclude /usr/local /usr scp://user@host/backup

would backup the /usr/local/bin directory (and its contents), but not /usr/local/doc.

The include, exclude, include-globbing-filelist, and exclude-globbing-filelist options accept extended shell globbing patterns. These patterns can contain the special patterns *, **, ?, and [...]. As in a normal shell, * can be expanded to any string of characters not containing "/", ? expands to any character except "/", and [...] expands to a single character of those characters specified (ranges are acceptable). The new special pattern, **, expands to any string of characters whether or not it contains "/". Furthermore, if the pattern starts with "ignorecase:" (case insensitive), then this prefix will be removed and any character in the string can be replaced with an upper- or lowercase version of itself.

Remember that you may need to quote these characters when typing them into a shell, so the shell does not interpret the globbing patterns before duplicity sees them.

The --exclude pattern option matches a file iff:

1.

pattern can be expanded into the file's filename, or

2.

the file is inside a directory matched by the option.

Conversely, --include pattern matches a file iff:

1.

pattern can be expanded into the file's filename,

2.

the file is inside a directory matched by the option, or

3.

the file is a directory which contains a file matched by the option.

For example,

--exclude /usr/local

matches /usr/local, /usr/local/lib, and /usr/local/lib/netscape. It is the same as --exclude /usr/local --exclude '/usr/local/**'.

--include /usr/local

specifies that /usr, /usr/local, /usr/local/lib, and /usr/local/lib/netscape (but not /usr/doc) all be backed up. Thus you don't have to worry about including parent directories to make sure that included subdirectories have somewhere to go. Finally,

--include ignorecase:'/usr/[a-z0-9]foo/*/**.py'

would match a file like /usR/5fOO/hello/there/world.py. If it did match anything, it would also match /usr. If there is no existing file that the given pattern can be expanded into, the option will not match /usr.

The --include-filelist, --exclude-filelist, --include-filelist-stdin, and --exclude-filelist-stdin options also introduce file selection conditions. They direct duplicity to read in a file, each line of which is a file specification, and to include or exclude the matching files. Lines are separated by newlines or nulls, depending on whether the --null-separator switch was given. Each line in a filelist is interpreted similarly to the way extended shell patterns are, with a few exceptions:

1.

Globbing patterns like *, **, ?, and [...] are not expanded.

2.

Include patterns do not match files in a directory that is included. So /usr/local in an include file will not match /usr/local/doc.

3.

Lines starting with "+ " are interpreted as include directives, even if found in a filelist referenced by --exclude-filelist. Similarly, lines starting with "- " exclude files even if they are found within an include filelist.

For example, if file "list.txt" contains the lines:

/usr/local

- /usr/local/doc

/usr/local/bin

+ /var

- /var

then "--include-filelist list.txt" would include /usr, /usr/local, and /usr/local/bin. It would exclude /usr/local/doc, /usr/local/doc/python, etc. It neither excludes nor includes /usr/local/man, leaving the fate of this directory to the next specification condition. Finally, it is undefined what happens with /var. A single file list should not contain conflicting file specifications.

The --include-globbing-filelist and --exclude-globbing-filelist options also specify filelists, but each line in the filelist will be interpreted as a globbing pattern the way --include and --exclude options are interpreted (although "+ " and "- " prefixing is still allowed). For instance, if the file "globbing-list.txt" contains the lines:

dir/foo

+ dir/bar

- **

Then "--include-globbing-filelist globbing-list.txt" would be exactly the same as specifying "--include dir/foo --include dir/bar --exclude **" on the command line.

Finally, the --include-regexp and --exclude-regexp allow files to be included and excluded if their filenames match a python regular expression. Regular expression syntax is too complicated to explain here, but is covered in Python's library reference. Unlike the --include and --exclude options, the regular expression options don't match files containing or contained in matched files. So for instance

--include '[0-9]{7}(?!foo)'

matches any files whose full pathnames contain 7 consecutive digits which aren't followed by 'foo'. However, it wouldn't match /home even if /home/ben/1234567 existed.

 

A NOTE ON EUROPEAN S3 BUCKETS

Amazon S3 provides the ability to choose the location of a bucket upon its creation. The purpose is to enable the user to choose a location which is better located network topologically relative to the user, because it may allow for faster data transfers.

duplicity will create a new bucket the first time a bucket access is attempted. At this point, the bucket will be created in Europe if --s3-european-buckets was given. For reasons having to do with how the Amazon S3 service works, this also requires the use of the --s3-use-new-style option. This option turns on subdomain based bucket addressing in S3. The details are beyond the scope of this man page, but it is important to know that your bucket must not contain upper case letters or any other characters that are not valid parts of a hostname. Consequently, for reasons of backwards compatibility, use of subdomain based bucket addressing is not enabled by default.

Note that you will need to use --s3-use-new-style for all operations on European buckets; not just upon initial creation.

You only need to use --s3-european-buckets upon initial creation, but you may may use it at all times for consistency.

Further note that when creating a new European bucket, it can take a while before the bucket is fully accessible. At the time of this writing it is unclear to what extent this is an expected feature of Amazon S3, but in practice you may experience timeouts, socket errors or HTTP errors when trying to upload files to your newly created bucket. Give it a few minutes and the bucket should function normally.

 

A NOTE ON IMAP

An IMAP account can be used as a target for the upload. The userid may be specified and the password will be requested.

The from_address_prefix may be specified (and probably should be). The text will be used as the "From" address in the IMAP server. Then on a restore (or list) command the from_address_prefix will distinguish between different backups.

 

A NOTE ON UBUNTU ONE

Connecting to Ubuntu One requires that you be running duplicity inside of an X session so that you can be prompted for your credentials if necessary by the Ubuntu One session daemon.

See https://one.ubuntu.com/ for more information about Ubuntu One.

 

A NOTE ON SYMMETRIC ENCRYPTION AND SIGNING

Signing and symmetrically encrypt at the same time with the gpg binary on the command line, as used within duplicity, is a specifically challenging issue. Tests showed that the following combinations proved working.

1. Setup gpg-agent properly. Use the option --use-agent and enter both passphrases (symmetric and sign key) in the gpg-agent's dialog.

2. Use a PASSPHRASE for symmetric encryption of your choice but the signing key has an empty passphrase.

3. The used PASSPHRASE for symmetric encryption and the passphrase of the signing key are identical.

 

KNOWN ISSUES / BUGS

Hard links currently unsupported (they will be treated as non-linked regular files).

Bad signatures will be treated as empty instead of logging appropriate error message.

 

OPERATION AND DATA FORMATS

This section describes duplicity's basic operation and the format of its data files. It should not necessary to read this section to use duplicity.

The files used by duplicity to store backup data are tarfiles in GNU tar format. They can be produced independently by rdiffdir(1). For incremental backups, new files are saved normally in the tarfile. But when a file changes, instead of storing a complete copy of the file, only a diff is stored, as generated by rdiff(1). If a file is deleted, a 0 length file is stored in the tar. It is possible to restore a duplicity archive "manually" by using tar and then cp, rdiff, and rm as necessary. These duplicity archives have the extension difftar.

Both full and incremental backup sets have the same format. In effect, a full backup set is an incremental one generated from an empty signature (see below). The files in full backup sets will start with duplicity-full while the incremental sets start with duplicity-inc. When restoring, duplicity applies patches in order, so deleting, for instance, a full backup set may make related incremental backup sets unusable.

In order to determine which files have been deleted, and to calculate diffs for changed files, duplicity needs to process information about previous sessions. It stores this information in the form of tarfiles where each entry's data contains the signature (as produced by rdiff) of the file instead of the file's contents. These signature sets have the extension sigtar.

Signature files are not required to restore a backup set, but without an up-to-date signature, duplicity cannot append an incremental backup to an existing archive.

To save bandwidth, duplicity generates full signature sets and incremental signature sets. A full signature set is generated for each full backup, and an incremental one for each incremental backup. These start with duplicity-full-signatures and duplicity-new-signatures respectively. These signatures will be stored both locally and remotely. The remote signatures will be encrypted if encryption is enabled. The local signatures will not be encrypted and stored in the archive dir (see --archive-dir ).

 

AUTHOR

Original Author - Ben Escoto <bescoto@stanford.edu>

Current Maintainer - Kenneth Loafman <kenneth@loafman.com>

 

SEE ALSO

rdiffdir(1), python(1), rdiff(1), rdiff-backup(1).

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Index

NAME

SYNOPSIS

DESCRIPTION

EXAMPLES

ACTIONS

OPTIONS

ENVIRONMENT VARIABLES

URL FORMAT

TIME FORMATS

FILE SELECTION

A NOTE ON EUROPEAN S3 BUCKETS

A NOTE ON IMAP

A NOTE ON UBUNTU ONE

A NOTE ON SYMMETRIC ENCRYPTION AND SIGNING

KNOWN ISSUES / BUGS

OPERATION AND DATA FORMATS

AUTHOR

SEE ALSO

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