# btrbk
<!-- TOC -->
* [btrbk](#btrbk)
* [General](#general)
* [Snapshots and Backups](#snapshots-and-backups)
* [Actions and Informative Commands](#actions-and-informative-commands)
* [run [filter...]](#run-filter)
* [clean [filter...]](#clean-filter)
* [stats [filter...]](#stats-filter)
* [diff <from> <to>](#diff-from-to)
* [Cleanup](#cleanup)
* [Configuration](#configuration)
* [General](#general-1)
* [Retention](#retention)
* [SSH and Data Stream Options](#ssh-and-data-stream-options)
* [System Options](#system-options)
* [Example: Local Snapshots and Backup](#example-local-snapshots-and-backup)
* [Testing on Local Host](#testing-on-local-host)
* [NixOS Config](#nixos-config)
* [pi3bplus Host Config](#pi3bplus-host-config)
<!-- TOC -->
## General
* https://digint.ch/btrbk/doc/readme.html
* https://digint.ch/btrbk/doc/btrbk.1.html
* https://digint.ch/btrbk/doc/btrbk.conf.5.html
> btrbk - backup tool for btrfs subvolumes
- Take snapshots (on same disk)
- Create multiple backups (on different disks) over SSH
Further resources:
- https://nixos.wiki/wiki/Btrbk
- https://wiki.gentoo.org/wiki/Btrbk
## Snapshots and Backups
subvolume: <subvolume-name>
snapshot: <snapshot-name>.<timestamp>\[<N>]
timestamp: Can be configured using the `timestamp_format` option.
N: If multiple snapshots are created at the same time, the increasing counter N differentiates them.
## Actions and Informative Commands
### run [filter...]
In multiple steps, perform snapshots and backups.
* Read Data: Perform sanity checks
* Create Snapshots
* Create Backups
* Delete Backups
* Delete Snapshots
### clean [filter...]
Delete incomplete backups (network error, kill signal while send/receive was ongoing).
### stats [filter...]
Print statistics of snapshot and backup subvolumes.
```shell
sudo btrbk -c /etc/btrbk/local-backup-hdd.conf stats
```
```console
SOURCE_SUBVOLUME SNAPSHOT_SUBVOLUME TARGET_SUBVOLUME SNAPSHOTS BACKUPS
/mnt/data/jc-data/cloud.fykml.eu /mnt/data/snap2/cloud.fykml.eu.* /mnt/backup/snap2/cloud.fykml.eu.* 77 17
/mnt/data/jc-data/cloud.privacy1st.de /mnt/data/snap2/cloud.privacy1st.de.* /mnt/backup/snap2/cloud.privacy1st.de.* 77 17
Total:
154 snapshots
34 backups (34 correlated)
```
### diff <from> <to>
List the modified files since generation (transid) of subvolume <from> in subvolume <to>.
Columns:
```
SIZE file was modified for a total of SIZE bytes
COUNT file was modified in COUNT generations
FLAGS "+" file accessed at offset 0 (at least once)
"c" COMPRESS flag is set (at least once)
"i" INLINE flag is set (at least once)
```
```shell
sudo btrbk -c /etc/btrbk/local-backup-hdd.conf diff cloud.privacy1st.de.20240222T2300 cloud.privacy1st.de.20240223T1400
```
```console
FLAGS COUNT SIZE FILE
+c. 1 2.36 MiB data/appdata_oc2uzw0ocw65/appstore/apps.json
+.. 1 12.00 KiB data/appdata_oc2uzw0ocw65/preview/a/3/f/c/b/b/7/5105712/256-256-crop.jpg
+.. 1 24.00 KiB data/appdata_oc2uzw0ocw65/preview/a/3/f/c/b/b/7/5105712/384-512-max.jpg
+.. 1 8.00 KiB data/appdata_oc2uzw0ocw65/preview/d/8/4/f/d/0/7/5105717/256-256-crop.jpg
+.. 1 20.00 KiB data/appdata_oc2uzw0ocw65/preview/d/8/4/f/d/0/7/5105717/384-512-max.jpg
+c. 1 208.00 KiB data/appdata_oc2uzw0ocw65/suspicious_login/models/527
... 18 324.00 KiB data/nextcloud.log
... 257 40.21 MiB db/binlog.000119
... 290 48.11 MiB db/ib_logfile0
+c. 5 5.59 MiB db/ibdata1
.c. 4 112.00 KiB db/mysql/innodb_index_stats.ibd
.c. 1 32.00 KiB db/mysql/innodb_table_stats.ibd
+.. 3 264.00 KiB db/nextcloud/oc_activity.ibd
.c. 1 32.00 KiB db/nextcloud/oc_activity_mq.ibd
... 2 16.00 KiB db/nextcloud/oc_appconfig.ibd
+.. 3 88.00 KiB db/nextcloud/oc_authtoken.ibd
... 4 40.00 KiB db/nextcloud/oc_calendar_reminders.ibd
... 3 40.00 KiB db/nextcloud/oc_calendarchanges.ibd
+.. 6 184.00 KiB db/nextcloud/oc_calendarobjects.ibd
+.. 4 232.00 KiB db/nextcloud/oc_calendarobjects_props.ibd
.c. 1 8.00 KiB db/nextcloud/oc_calendarsubscriptions.ibd
... 8 1.18 MiB db/nextcloud/oc_filecache.ibd
... 2 48.00 KiB db/nextcloud/oc_filecache_extended.ibd
... 1 32.00 KiB db/nextcloud/oc_gpodder_episode_action.ibd
... 2 48.00 KiB db/nextcloud/oc_jobs.ibd
+c. 1 48.00 KiB db/nextcloud/oc_login_address.ibd
... 3 64.00 KiB db/nextcloud/oc_login_ips_aggregated.ibd
... 1 40.00 KiB db/nextcloud/oc_maps_photos.ibd
... 1 24.00 KiB db/nextcloud/oc_news_feeds.ibd
+.. 9 4.98 MiB db/nextcloud/oc_news_items.ibd
... 4 64.00 KiB db/nextcloud/oc_notifications.ibd
.c. 2 24.00 KiB db/nextcloud/oc_notifications_settings.ibd
... 1 16.00 KiB db/nextcloud/oc_preferences.ibd
... 1 16.00 KiB db/nextcloud/oc_preview_generation.ibd
... 1 16.00 KiB db/nextcloud/oc_suspicious_login_model.ibd
Total size: 104.47 MiB
```
## Cleanup
- Adjustments: It is possible to change `2d` to something else, e.g. `no` to keep only the latest snapshot/backup.
- **Warning**: If all except the latest snapshots and backups are deleted on `yodaNas`, then the next backup to `yodaHedgehog` will be **non-incremental**! Make sure to keep at least one snapshot/backup per subvolume on `yodaNas` that has already been copied to `yodaHedgehog`. Or use a config file that covers local (`yodaNas`) and remote (`yodahedgehog`) backups!
- First, perform a dryrun. Double-check the output. Then, replace `dryrun` with `run`.
```shell
sudo btrbk -c /etc/btrbk/local-backup-ssd.conf \
--override=snapshot_preserve=2d \
--override=snapshot_preserve_min=latest \
--override=snapshot_create=no \
--override=target_preserve=2d \
--override=target_preserve_min=latest \
--print-schedule \
dryrun
```
```console
SNAPSHOT SCHEDULE
-----------------
ACTION SUBVOLUME SCHEME REASON
delete /mnt/data/snap2/cloud.privacy1st.de.20230927T1827 2d (sunday, 00:00) -
...
delete /mnt/data/snap2/cloud.privacy1st.de.20240220T0000 2d (sunday, 00:00) -
- /mnt/data/snap2/cloud.privacy1st.de.20240221T0000 2d (sunday, 00:00) preserve daily: first of day, 2 days ago, at 00:00
delete /mnt/data/snap2/cloud.privacy1st.de.20240221T0100 2d (sunday, 00:00) -
...
delete /mnt/data/snap2/cloud.privacy1st.de.20240221T2300 2d (sunday, 00:00) -
- /mnt/data/snap2/cloud.privacy1st.de.20240222T0000 2d (sunday, 00:00) preserve daily: first of day, 1 days ago, at 00:00
delete /mnt/data/snap2/cloud.privacy1st.de.20240222T0100 2d (sunday, 00:00) -
...
delete /mnt/data/snap2/cloud.privacy1st.de.20240222T2300 2d (sunday, 00:00) -
- /mnt/data/snap2/cloud.privacy1st.de.20240223T0000 2d (sunday, 00:00) preserve daily: first of day, 0 days ago, at 00:00
delete /mnt/data/snap2/cloud.privacy1st.de.20240223T0100 2d (sunday, 00:00) -
...
delete /mnt/data/snap2/cloud.privacy1st.de.20240223T1500 2d (sunday, 00:00) -
- /mnt/data/snap2/cloud.privacy1st.de.20240223T1600 2d (sunday, 00:00) preserve min: latest
BACKUP SCHEDULE
---------------
ACTION SUBVOLUME SCHEME REASON
delete /mnt/backup/snap2/cloud.privacy1st.de.20230927T1827 2d (sunday, 00:00) -
...
delete /mnt/backup/snap2/cloud.privacy1st.de.20240220T0000 2d (sunday, 00:00) -
- /mnt/backup/snap2/cloud.privacy1st.de.20240221T0000 2d (sunday, 00:00) preserve daily: first of day, 2 days ago, at 00:00
- /mnt/backup/snap2/cloud.privacy1st.de.20240222T0000 2d (sunday, 00:00) preserve daily: first of day, 1 days ago, at 00:00
- /mnt/backup/snap2/cloud.privacy1st.de.20240223T0000 2d (sunday, 00:00) preserve daily: first of day, 0 days ago, at 00:00
- /mnt/backup/snap2/cloud.privacy1st.de.20240223T1600 2d (sunday, 00:00) preserve min: latest
```
## Configuration
### General
`volume <volume-directory|<ulr>`: Usually the mount point of a btrfs filesystem mounted with `subvolid=5`.
`subvolume <subvolume-name|<url>`: Subvolume to be backed up, relative to `<volume-directory>`.
`snapshot_dir <directory>`: Directory in which the btrfs snapshots are created, relative to `<volume-directory>`. Hast to be created **manually**!
`target <target-directory>|<url>`: Target directory where the backup subvolumes are to be created. Multiple target sections are allowed.
`url`: Accepted formats are:
* `ssh://<hostname>[:<port>]/<directory>`
* `<hostname>:<directory>`
`hostname`: Either a host name, IPv4 or IPv6 address
`timestamp_format short|long|long-iso`: This becomes relevant for setups with multiple btrbk instances, e.g. many snapshot-only instances (spread around the world), and a fetch-only instance on the backup server. Make sure to run btrbk with the same time zone on every host, e.g. by setting the TZ environment variable (see tzset(3)).
### Retention
`snapshot_preserve <retention_policy>`
`snapshot_preserve_min all|latest|<number>{h,d,w,m,y}`: Preserve all snapshots for a minimum amount of hours (h), days (d), weeks (w), months (m) or years (y).
`target_preserve <retention_policy>`
`target_preserve_min all|latest|no|<number>{h,d,w,m,y}`: Preserve all snapshots for a minimum amount of hours (h), days (d), weeks (w), months (m) or years (y). If set to "no", only the backups following the `target_preserve` policy are created.
`<retention_policy>`: `[<hourly>h] [<daily>d] [<weekly>w] [<monthly>m] [<yearly>y]`. Defines how many backups of each period should be preserved.
### SSH and Data Stream Options
`ssh_compression yes|no`
`stream_compress <compress_command>`: Compress the btrfs send stream before transferring it from/to remote locations.
`<compress_command>`: gzip, pigz, bzip2, pbzip2, bzip3, xz, lzo, lz4, zstd.
`stream_buffer <size>|no`: This can give a speed improvement (measured up to 20%) on both local or remote operations, but also increases system load. Make sure that the `mbuffer` command is available. Leave this option disabled if your main concern is a stable backup process: while recent versions of mbuffer have proven reliable, it is often desirable to keep things simple rather than adding an additional, multi-threaded process to the command pipe.
`rate_limit <rate>|no`: Limit the read rate of the btrfs send stream to `<rate>` bytes per second. Implies the `stream_buffer` option.
### System Options
`transaction_syslog <facility>|no`: Log all transactions to syslog.
`lockfile <file>|no`
## Example: Local Snapshots and Backup
```
timestamp_format long
snapshot_preserve_min 2d
snapshot_preserve 24h 7d 4w 6m
target_preserve_min no
target_preserve 7d 4w 6m
volume /mnt/12tb1-top-level
snapshot_dir @snap
target /mnt/12tb2-top-level/@snap
subvolume @home
subvolume @
```
Mount top-level subvolume:
```shell
mount -o subvolid=5 /dev/mapper/some-disk /mnt/12tb1-top-level
```
Manually create snapshot directory:
```shell
btrfs subvolume create /mnt/12tb1-top-level/@snap
btrfs subvolume create /mnt/12tb2-top-level/@snap
```
Snapshots only:
```shell
btrbk snapshot
```
Backup only:
```shell
btrbk resume
```
Create an additional snapshot of @home:
```shell
btrbk snapshot @home
```
## Testing on Local Host
```shell
sudo mkdir -p /mnt/top-level
ls /mnt/top-level/@ || sudo mount -o subvolid=5 /dev/mapper/luks-ea7099e3-320d-4eb3-a4c3-9910a9af817b /mnt/top-level
ls /mnt/top-level/@snap || sudo btrfs subvolume create /mnt/top-level/@snap
ls /mnt/top-level/@foo || {
sudo btrfs subvolume create /mnt/top-level/@foo
sudo touch /mnt/top-level/@foo/bar
}
```
```shell
ls ~/btrbk-usb.img || {
fallocate -l 1G ~/btrbk-usb.img
sudo mkfs.btrfs ~/btrbk-usb.img
# Mount and create subvolume @
}
sudo mkdir -p /mnt/usb-top-level
ls /mnt/usb-top-level/@ || sudo mount -o subvolid=5 ~/btrbk-usb.img /mnt/usb-top-level
ls /mnt/usb-top-level/@snap || sudo btrfs subvolume create /mnt/usb-top-level/@snap
}
```
```shell
cat > ~/btrbk.cfg <<'EOF'
timestamp_format long
snapshot_preserve_min 2d
snapshot_preserve 24h 7d 4w 6m
target_preserve_min no
target_preserve 7d 4w 6m
volume /mnt/top-level
snapshot_dir @snap
target /mnt/usb-top-level/@snap
subvolume @foo
EOF
```
```shell
# Check configuration.
sudo btrbk -c ~/btrbk.cfg config print
sudo btrbk -c ~/btrbk.cfg config list
# Dry run.
sudo btrbk -c ~/btrbk.cfg run -n
# Create first snapshot.
sudo btrbk -c ~/btrbk.cfg run
# Print schedule.
sudo btrbk -c ~/btrbk.cfg run -n -S
sleep 5m
sudo btrbk -c ~/btrbk.cfg run
# List snapshots
sudo btrbk -c ~/btrbk.cfg list
```
### NixOS Config
```nix
{ config, pkgs, ... }:
{
services.btrbk = {
# Lowest scheduling priority.
niceness = 19;
# Set of btrbk instances. The instance named btrbk is the default one.
instances = {
# This is the configuration equivalent to
# README.md section "Testing on Local Host".
"testing-on-local-host" = {
# The timer is disabled. The service has to be invoked manually.
onCalendar = null;
#onCalendar = "hourly";
#onCalendar = "*:0/15"; # Every 15min
# Configuration options for btrbk. Nested attrsets translate to subsections.
settings = {
timestamp_format = "long";
stream_compress = "lz4";
snapshot_preserve_min = "2d";
snapshot_preserve = "24h 7d 4w 6m";
target_preserve_min = "no";
target_preserve = "7d 4w 6m";
volume."/mnt/top-level" = {
snapshot_dir = "@snap";
target = "/mnt/usb-top-level/@snap";
subvolume = "@foo";
};
};
};
};
};
}
```
## pi3bplus Host Config
A local `btrbk` instance manages snapshots and local backups.
Another remote backup server periodically pulls snapshots to create remote backups. Here is its config:
```shell
cat > ~/btrbk.cfg <<'EOF'
timestamp_format long
stream_compress lz4
ssh_identity /mnt/backup/rootNas_ed25519
# Create backups.
target_preserve_min no
# Daily backups -> @daily cron entry
target_preserve 7d 4w 6m
# Hourly backups -> @hourly cron entry
#target_preserve 24h 7d 4w 6m
# Don't create or delete snapshots on remote server "rootNas".
snapshot_preserve_min all
snapshot_create no
volume ssh://rootNas/jc-data
snapshot_dir /snap
target /mnt/backup/snap
subvolume arch.p1st.de
subvolume blogger.privacy1st.de
subvolume changedetection.p1st.de
subvolume cloud.privacy1st.de
subvolume git.privacy1st.de
subvolume mastodon-toot-follower.privacy1st.de
subvolume money.p1st.de
subvolume music.privacy1st.de
subvolume paste.p1st.de
subvolume proxy
subvolume recipe.privacy1st.de
subvolume traggo.privacy1st.de
volume ssh://rootNas/mnt/data/jc-data
snapshot_dir /mnt/data/snap2
target /mnt/backup/snap2
subvolume cloud.privacy1st.de
subvolume cloud.fykml.eu
EOF
```