borg-prune(1)

Name
borg-prune - Prune archives according to specified rules.

SYNOPSIS

borg [common options] prune [options] [NAME]

DESCRIPTION

The prune command prunes a repository by soft-deleting all archives not matching any of the specified retention options.

Important:

•   The prune command will only mark archives for deletion ("soft-deletion"), repository disk space is not freed until you run borg compact.

•   You can use borg undelete to undelete archives, but only until you run borg compact.

    This command is normally used by automated backup scripts wanting to keep a certain number of historic backups. This retention policy is commonly referred to as GFS <https://en.wikipedia.org/wiki/Backup_rotation_scheme#Grandfather-father-son> (Grandfather-father-son) backup rotation scheme.

    The recommended way to use prune is to give the archive series name to it via the NAME argument (assuming you have the same name for all archives in a series). Alternatively, you can also use --match-archives (-a), then only archives that match the pattern are considered for deletion and only those archives count towards the totals specified by the rules. Otherwise, all archives in the repository are candidates for deletion! There is no automatic distinction between archives representing different contents. These need to be distinguished by specifying matching globs.

    If you have multiple series of archives with different data sets (e.g. from different machines) in one shared repository, use one prune call per series.

    The --keep-within option takes an argument of the form "<int><char>", where char is "y", "m", "w", "d", "H", "M", or "S". For example, --keep-within 2d means to keep all archives that were created within the past 2 days. "1m" is taken to mean "31d". The archives kept with this option do not count towards the totals specified by any other options.

    A good procedure is to thin out more and more the older your backups get. As an example, --keep-daily 7 means to keep the latest backup on each day, up to 7 most recent days with backups (days without backups do not count). The rules are applied from secondly to yearly, and backups selected by previous rules do not count towards those of later rules. The time that each backup starts is used for pruning purposes. Dates and times are interpreted in the local timezone of the system where borg prune runs, and weeks go from Monday to Sunday. Specifying a negative number of archives to keep means that there is no limit.

    Borg will retain the oldest archive if any of the secondly, minutely, hourly, daily, weekly, monthly, quarterly, or yearly rules was not otherwise able to meet its retention target. This enables the first chronological archive to continue aging until it is replaced by a newer archive that meets the retention criteria.

    The --keep-13weekly and --keep-3monthly rules are two different strategies for keeping archives every quarter year.

    The --keep-last N option is doing the same as --keep-secondly N (and it will keep the last N archives under the assumption that you do not create more than one backup archive in the same second).

    You can influence how the --list output is formatted by using the --short option (less wide output) or by giving a custom format using --format (see the borg repo-list description for more details about the format string).

OPTIONS

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

  arguments

NAME
    specify the archive name

  options

-n, --dry-run
    do not change the repository

--list
    output a verbose list of archives it keeps/prunes

--short
    use a less wide archive part format

--list-pruned
    output verbose list of archives it prunes

--list-kept
    output verbose list of archives it keeps

--format FORMAT
    specify format for the archive part (default: "{archive:<36} {time} [{id}]")

--keep-within INTERVAL
    keep all archives within this time interval

--keep-last, --keep-secondly
    number of secondly archives to keep

--keep-minutely
    number of minutely archives to keep

-H, --keep-hourly
    number of hourly archives to keep

-d, --keep-daily
    number of daily archives to keep

-w, --keep-weekly
    number of weekly archives to keep

-m, --keep-monthly
    number of monthly archives to keep

--keep-13weekly
    number of quarterly archives to keep (13 week strategy)

--keep-3monthly
    number of quarterly archives to keep (3 month strategy)

-y, --keep-yearly
    number of yearly archives to keep

  Archive filters

-a PATTERN, --match-archives PATTERN
    only consider archives matching all patterns. See "borg help match-archives".

--oldest TIMESPAN
    consider archives between the oldest archive's timestamp and (oldest + TIMESPAN), e.g., 7d or 12m.

--newest TIMESPAN
    consider archives between the newest archive's timestamp and (newest - TIMESPAN), e.g., 7d or 12m.

--older TIMESPAN
    consider archives older than (now - TIMESPAN), e.g., 7d or 12m.

--newer TIMESPAN
    consider archives newer than (now - TIMESPAN), e.g., 7d or 12m.

EXAMPLES

Be careful: prune is a potentially dangerous command that removes backup archives.

By default, prune applies to all archives in the repository unless you restrict its operation to a subset of the archives.

The recommended way to name archives (with borg create) is to use the identical archive name within a series of archives. Then you can simply give that name to prune as well, so it operates only on that series of archives.

Alternatively, you can use -a/--match-archives to match archive names and select a subset of them. When using -a, be careful to choose a good pattern — for example, do not use a prefix "foo" if you do not also want to match "foobar".

It is strongly recommended to always run prune -v --list --dry-run ... first, so you will see what it would do without it actually doing anything.

Do not forget to run borg compact -v after prune to actually free disk space.

    # Keep 7 end of day and 4 additional end of week archives.
    # Do a dry-run without actually deleting anything.
    $ borg prune -v --list --dry-run --keep-daily=7 --keep-weekly=4
    # Similar to the above, but only apply to the archive series named '{hostname}':
    $ borg prune -v --list --keep-daily=7 --keep-weekly=4 '{hostname}'
    # Similar to the above, but apply to archive names starting with the hostname
    # of the machine followed by a '-' character:
    $ borg prune -v --list --keep-daily=7 --keep-weekly=4 -a 'sh:{hostname}-*'
    # Keep 7 end of day, 4 additional end of week archives,
    # and an end of month archive for every month:
    $ borg prune -v --list --keep-daily=7 --keep-weekly=4 --keep-monthly=-1
    # Keep all backups in the last 10 days, 4 additional end of week archives,
    # and an end of month archive for every month:
    $ borg prune -v --list --keep-within=10d --keep-weekly=4 --keep-monthly=-1

There is also a visualized prune example in docs/misc/prune-example.txt.

SEE ALSO

borg-common(1), borg-compact(1)

Author
The Borg Collective