borg [common options] prune [options] [NAME]
positional arguments |
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specify the archive name |
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optional arguments |
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do not change repository |
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output verbose list of archives it keeps/prunes |
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use a less wide archive part format |
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output verbose list of archives it prunes |
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output verbose list of archives it keeps |
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specify format for the archive part (default: “{archive:<36} {time} [{id}]”) |
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keep all archives within this time interval |
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number of secondly archives to keep |
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number of minutely archives to keep |
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number of hourly archives to keep |
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number of daily archives to keep |
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number of weekly archives to keep |
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number of monthly archives to keep |
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number of quarterly archives to keep (13 week strategy) |
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number of quarterly archives to keep (3 month strategy) |
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number of yearly archives to keep |
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Archive filters — Archive filters can be applied to repository targets. |
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only consider archives matching all patterns. see “borg help match-archives”. |
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consider archives between the oldest archive’s timestamp and (oldest + TIMESPAN), e.g. 7d or 12m. |
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consider archives between the newest archive’s timestamp and (newest - TIMESPAN), e.g. 7d or 12m. |
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consider archives older than (now - TIMESPAN), e.g. 7d or 12m. |
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consider archives newer than (now - TIMESPAN), e.g. 7d or 12m. |
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.
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 “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.
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).
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.
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 also, so it operates just on that series of archives.
Alternatively, you can use -a
/ --match-archives
to do a match on the
archive names to select some of them.
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.
Don’t 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 as above but only apply to the archive series named '{hostname}':
$ borg prune -v --list --keep-daily=7 --keep-weekly=4 '{hostname}'
# Similar as 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
:
borg prune visualized
=====================
Assume it is 2016-01-01, today's backup has not yet been made, you have
created at least one backup on each day in 2015 except on 2015-12-19 (no
backup made on that day), and you started backing up with borg on
2015-01-01.
This is what borg prune --keep-daily 14 --keep-monthly 6 --keep-yearly 1
would keep.
Backups kept by the --keep-daily rule are marked by a "d" to the right,
backups kept by the --keep-monthly rule are marked by a "m" to the right,
and backups kept by the --keep-yearly rule are marked by a "y" to the
right.
Calendar view
-------------
2015
January February March
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1y 2 3 4 1 1
5 6 7 8 9 10 11 2 3 4 5 6 7 8 2 3 4 5 6 7 8
12 13 14 15 16 17 18 9 10 11 12 13 14 15 9 10 11 12 13 14 15
19 20 21 22 23 24 25 16 17 18 19 20 21 22 16 17 18 19 20 21 22
26 27 28 29 30 31 23 24 25 26 27 28 23 24 25 26 27 28 29
30 31
April May June
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1 2 3 4 5 1 2 3 1 2 3 4 5 6 7
6 7 8 9 10 11 12 4 5 6 7 8 9 10 8 9 10 11 12 13 14
13 14 15 16 17 18 19 11 12 13 14 15 16 17 15 16 17 18 19 20 21
20 21 22 23 24 25 26 18 19 20 21 22 23 24 22 23 24 25 26 27 28
27 28 29 30 25 26 27 28 29 30 31 29 30m
July August September
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1 2 3 4 5 1 2 1 2 3 4 5 6
6 7 8 9 10 11 12 3 4 5 6 7 8 9 7 8 9 10 11 12 13
13 14 15 16 17 18 19 10 11 12 13 14 15 16 14 15 16 17 18 19 20
20 21 22 23 24 25 26 17 18 19 20 21 22 23 21 22 23 24 25 26 27
27 28 29 30 31m 24 25 26 27 28 29 30 28 29 30m
31m
October November December
Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su Mo Tu We Th Fr Sa Su
1 2 3 4 1 1 2 3 4 5 6
5 6 7 8 9 10 11 2 3 4 5 6 7 8 7 8 9 10 11 12 13
12 13 14 15 16 17 18 9 10 11 12 13 14 15 14 15 16 17d18d19 20d
19 20 21 22 23 24 25 16 17 18 19 20 21 22 21d22d23d24d25d26d27d
26 27 28 29 30 31m 23 24 25 26 27 28 29 28d29d30d31d
30m
List view
---------
--keep-daily 14 --keep-monthly 6 --keep-yearly 1
----------------------------------------------------------------
1. 2015-12-31 (2015-12-31 kept (2015-12-31 kept
2. 2015-12-30 by daily rule) by daily rule)
3. 2015-12-29 1. 2015-11-30 1. 2015-01-01 (oldest)
4. 2015-12-28 2. 2015-10-31
5. 2015-12-27 3. 2015-09-30
6. 2015-12-26 4. 2015-08-31
7. 2015-12-25 5. 2015-07-31
8. 2015-12-24 6. 2015-06-30
9. 2015-12-23
10. 2015-12-22
11. 2015-12-21
12. 2015-12-20
(no backup made on 2015-12-19)
13. 2015-12-18
14. 2015-12-17
Notes
-----
2015-12-31 is kept due to the --keep-daily 14 rule (because it is applied
first), not due to the --keep-monthly or --keep-yearly rule.
The --keep-yearly 1 rule does not consider the December 31st backup because it
has already been kept due to the daily rule. There are no backups available
from previous years, so the --keep-yearly target of 1 backup is not satisfied.
Because of this, the 2015-01-01 archive (the oldest archive available) is kept.
The --keep-monthly 6 rule keeps Nov, Oct, Sep, Aug, Jul and Jun. December is
not considered for this rule, because that backup was already kept because of
the daily rule.
2015-12-17 is kept to satisfy the --keep-daily 14 rule - because no backup was
made on 2015-12-19. If a backup had been made on that day, it would not keep
the one from 2015-12-17.
We did not include weekly, hourly, minutely or secondly rules to keep this
example simple. They all work in basically the same way.
The weekly rule is easy to understand roughly, but hard to understand in all
details. If interested, read "ISO 8601:2000 standard week-based year".
The 13weekly and 3monthly rules are two different strategies for keeping one
every quarter of a year. There are `multiple ways` to define a quarter-year;
borg prune recognizes two:
* --keep-13weekly keeps one backup every 13 weeks using ISO 8601:2000's
definition of the week-based year. January 4th is always included in the
first week of a year, and January 1st to 3rd may be in week 52 or 53 of the
previous year. Week 53 is also in the fourth quarter of the year.
* --keep-3monthly keeps one backup every 3 months. January 1st to
March 31, April 1st to June 30th, July 1st to September 30th, and October 1st
to December 31st form the quarters.
If the subtleties of the definition of a quarter year don't matter to you, a
short summary of behavior is:
* --keep-13weekly favors keeping backups at the beginning of Jan, Apr, July,
and Oct.
* --keep-3monthly favors keeping backups at the end of Dec, Mar, Jun, and Sept.
* Both strategies will have some overlap in which backups are kept.
* The differences are negligible unless backups considered for deletion were
created weekly or more frequently.
.. _multiple ways: https://en.wikipedia.org/wiki/Calendar_year#Quarter_year