borg-prune - Prune repository archives according to specified rules
borg [common options] prune [options]
The prune command prunes a repository by deleting all archives not matching any
of the specified retention options.
Important: Repository disk space is
not freed 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 (Grandfather-father-son) backup rotation scheme.
Also, prune automatically removes checkpoint archives (incomplete archives left
behind by interrupted backup runs) except if the checkpoint is the latest
archive (and thus still needed). Checkpoint archives are not considered when
comparing archive counts against the retention limits (
--keep-X).
If you 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 sequences of archives with different data sets (e.g. from
different machines) in one shared repository, use one prune call per data set
that matches only the respective archives using the --match-archives (-a)
option.
The
--keep-within option takes an argument of the form
"<int><char>", where char is "H",
"d", "w", "m", "y". For example,
--keep-within 2d means to keep all archives that were created within
the past 48 hours. "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. As of borg 1.2.0, borg will retain the oldest archive if any of
the secondly, minutely, hourly, daily, weekly, monthly, 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-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).
When using
--stats, you will get some statistics about how much data was
deleted - the "Deleted data" deduplicated size there is most
interesting as that is how much your repository will shrink. Please note that
the "All archives" stats refer to the state after pruning.
See
borg-common(1) for common options of Borg commands.
- -n, --dry-run
- do not change repository
- --force
- force pruning of corrupted archives, use --force
--force in case --force does not work.
- -s, --stats
- print statistics for the deleted archive
- --list
- output verbose list of archives it keeps/prunes
-
--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
- -y, --keep-yearly
- number of yearly archives to keep
-
-c SECONDS, --checkpoint-interval SECONDS
- write checkpoint every SECONDS seconds (Default: 1800)
-
-a PATTERN, --match-archives PATTERN
- only consider archive names matching the pattern. 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 oder
12m.
-
--newer TIMESPAN
- consider archives newer than (now - TIMESPAN), e.g. 7d or
12m.
Be careful, prune is a potentially dangerous command, it will remove backup
archives.
The default of prune is to apply to
all archives in the repository unless
you restrict its operation to a subset of the archives using
-a /
--glob-archives. When using
-a, be careful to choose a good
pattern - e.g. 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.
# 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
# Same as above but only 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 '{hostname}-*'
# actually free disk space:
$ borg compact
# 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.
borg-common(1),
borg-compact(1)
The Borg Collective