NAME

btrbk − backup tool for btrfs volumes

SYNOPSIS

DESCRIPTION

btrbk is a backup tool for btrfs subvolumes, taking advantage of btrfs specific capabilities to create atomic snapshots and transfer them incrementally to target volumes. It is able to perform backups from one source to multiple destinations.

Snapshots as well as backup subvolume names are created in form:

<snapshot_name>.<timestamp>[_N]

Where <snapshot_name> is identical to the source subvolume name, unless the configuration option snapshot_name is set. The <timestamp> is either "YYYYMMDD" or "YYYYMMDDThhmm" (dependent of the timestamp_format configuration option), where "YYYY" is the year, "MM" is the month, "DD" is the day, "hh" is the hour and "mm" is the minute of the creation time (local time of the host running btrbk). If multiple snapshots/backups are created on the same date/time, N will be incremented on each backup, starting at 1.

OPTIONS

−h, −−help

Prints the synopsis and a list of the commands.

−−version

Prints the btrbk version.

−n, −−dry−run

Don’t run anything that would alter the filesystem, just show the snapshots and backup subvolumes that would be created/deleted by the run and clean commands. Use in conjunction with −l debug to see the btrfs commands that would be executed.

−c, −−config <file>

Read the configuration from <file>.

−p, −−preserve

Preserve all backups. Skips deletion of old backups, even if specified in the configuration file.

−r, −−resume-only

Resume only. Skips snapshot creation, only resumes missing backups. This only makes sense if the resume_missing option is set to “yes” in the configuration file.

−v, −−verbose

Verbose output. Sets "−l info", and prints detailed scheduler information on "run" and "dryrun" commands.

−q, −−quiet

Quiet operation. If set, btrbk does not print the summary after executing the "run" command.

−l, −−loglevel <level>

Set the level of verbosity. Accepted levels are warn, info, debug, and trace.

−t, −−table

Print output in table format (shortcut for "--format=table").

−−format table|long|raw

Print output in specified format. If set to "raw", prints space-separated key="value" pairs (machine-readable). Affects output format for run, dryrun, list and tree commands. Useful for further exporting/scripting.

−−progress

Show progress bar on send-receive operation.

COMMANDS

run [filter...]

Perform backup operations as specified in the configuration file. If the optional [filter...] arguments are present, backups are only performed for the subvolumes/targets matching a FILTER STATEMENT (see below).

First, btrbk reads information from the source and target btrfs filesystems in order to perform sanity checks and identify parent/child and received-from relationships.

If the checks succeed, btrbk creates snapshots for all the source subvolumes specified in the configuration file.

Then, for each specified target, btrbk creates the backups as follows: If the resume_missing option is set (the default), btrbk transfers all missing snapshots needed to satisfy the configured target_preserve_{daily,weekly,monthly} retention policy, always incrementally from the latest common parent subvolume found. If no common parent subvolume is found, a full backup is created for the first transfer. Note that the latest snapshot (the one created in the first step) is always transferred, regardless of the retention policy.

As a last step, unless the -p (preserve backups) option is set, snapshots and backup subvolumes that are not preserved by their configured retention policy will be deleted. Note that the latest snapshot as well as the latest backup is always preserved, regardless of the retention policy.

Use the −−format command line option to switch between different output formats.

dryrun [filter...]

Don’t run any btrfs commands that would alter the filesystem, just show the snapshots and backup subvolumes that would be created/deleted by the run command. Use in conjunction with −l debug to see the btrfs commands that would be executed.

stats [filter...]

Print statistics of snapshot and backup subvolumes. Optionally filtered by [filter...] arguments (see FILTER STATEMENTS below).

list <subcommand> [filter...]

Print information defined by <subcommand> in a tabular form. Optionally filtered by [filter...] arguments (see FILTER STATEMENTS below).

Available subcommands:

	snapshots		All snapshots (and corresponding backups).
	backups		All backups (and corresponding snapshots).
	latest		Most recent snapshots and backups.
	config		Configured source/snapshot/target relations.
	source		Configured source/snapshot relations.
	volume		Configured volume sections.
	target		Configured targets.

Use the −−format command line option to switch between different output formats.

clean [filter...]

Delete incomplete (garbled) backups. Incomplete backups can be left behind on network errors or kill signals while a send/receive operation is ongoing, and are identified by the "received_uuid" flag not being set on a target (backup) subvolume.

usage [filter...]

Print filesystem usage information for all source/target volumes. Optionally filtered by [filter...] arguments (see FILTER STATEMENTS below).

origin <subvolume>

Print origin information for the given backup subvolume, showing the parent-child relationship as well as the received-from information.

diff <from> <to>

Print new files since subvolume <from> for subvolume <to>.

config print|print-all

Prints the parsed configuration file. Use the −−format command line option to switch between different output formats.

FILTER STATEMENTS

Filter arguments are accepted in form:

[hostname:]<volume-directory>

Matches all subvolumes and targets of a volume configuration section.

[hostname:]<volume-directory>/<subvolume-name>

Matches the specified subvolume and all targets of a subvolume configuration section.

[hostname:]<target-directory>

Matches all targets of a target configuration section.

[hostname:]<target-directory>/<snapshot-name>

Matches a single target of a target section within a subvolume section with given <snapshot-name>.

<group-name>

Matches the group configuration option of a volume, subvolume or target section.

For convenience, [hostname:] can be specified as either "hostname:" or "ssh://hostname/".

FILES

/etc/btrbk.conf
/etc/btrbk/btrbk.conf

Default configuration file. The file format and configuration options are described in btrbk.conf(5).

EXIT STATUS

btrbk returns the following error codes:

0		No problems occurred.
1		Generic error code.
2		Parse error: when parsing command-line options or configuration file.
10		Backup abort: At least one backup task aborted.
255		Script error.

AVAILABILITY

Please refer to the btrbk project page http://www.digint.ch/btrbk/ for further details.

AUTHOR

Axel Burri <axel@tty0.ch>

Document Archive: btrbk-0.22.1

btrbk-0.22.1