====== Borgmatic ======
[[https://torsion.org/borgmatic/|Borgmatic]] is a software to automate [[borg|Borg]] [[.:|backups]].

===== Deduplication =====
You have to use the same repository for deduplication to work. So if you'd like to deduplicate blocks for all your workstations, they have to connect to the same repository.

===== Backup per Application =====

Borgmatic can be configured to back up different services (generally meaning particular directories on your system) with different configurations.  Configurations are given to Borgmatic using .yaml files and can be specified as a launch option.  A sample configuration file is as follows:

<file yaml /etc/borgmatic/example.yaml>
location:
    source_directories:
        - /path/to/source
    repositories:
        - backup:/path/to/backup

storage:
    encryption_passphrase: "example password"
    compression: lz4
    remote_rate_limit: 10000
    archive_name_format: '{hostname}-my_service-{now:%Y-%m-%dT%H:%M:%S}'

retention:
    prefix: "{hostname}-my_service-"
    keep_daily: 7
    keep_weekly: 4
    keep_monthly: 12
    keep_yearly: 2

consistency:
    checks:
        - disabled
</file>

===== Automating backups with Systemd =====

[[admin:linux:systemd|Systemd]] can be used to run Borgmatic on a schedule.  This will require a two-part setup, using a systemd service and corresponding timer.  This is configured using an instantiated service for flexibility as follows:

<file ini /etc/systemd/system/borgmatic@.service>
[Unit]
Description=backup %i with borgmatic
Wants=network-online.target
After=network-online.target
ConditionACPower=true

[Service]
Type=oneshot

# Lower CPU and I/O priority.
Nice=19
CPUSchedulingPolicy=batch
IOSchedulingClass=best-effort
IOSchedulingPriority=7
IOWeight=100

Restart=no
# Prevent rate limiting of borgmatic log events. If you are using an older version of systemd that
# doesn't support this (pre-240 or so), you may have to remove this option.
LogRateLimitIntervalSec=0

# Delay start to prevent backups running during boot. Note that systemd-inhibit requires dbus and
# dbus-user-session to be installed.
ExecStart=systemd-inhibit --who="borgmatic-%i" --why="Prevent interrupting backup of %I" /your/borgmatic/path-c /etc/borgmatic/%i.yaml --syslog-verbosity 1
</file>

Multiple timer rules can be created to run at different intervals if desired.  The following timer will run a daily backup:

<file ini /etc/systemd/system/borgmatic-nightly@.timer>
[Unit]
Description=%j backups for %i

[Timer]
Unit=borgmatic@%i.service
OnCalendar=*-*-* 03:30:00
RandomizedDelaySec=15min

[Install]
WantedBy=timers.target
</file>

==== backing up Docker Compose stacks ====
<file ini /etc/systemd/system/borgmatic-compose@.service>
[Unit]
Description=backup of docker-compose service %i with borgmatic
Wants=network-online.target
After=network-online.target
ConditionACPower=true

[Service]
ExecStartPre=systemctl stop docker-compose@%i.service
Type=oneshot
# Lower CPU and I/O priority.
Nice=19
CPUSchedulingPolicy=batch
IOSchedulingClass=best-effort
IOSchedulingPriority=7
IOWeight=100

Restart=no
# Prevent rate limiting of borgmatic log events. If you are using an older version of systemd that
# doesn't support this (pre-240 or so), you may have to remove this option.
LogRateLimitIntervalSec=0

# Delay start to prevent backups running during boot. Note that systemd-inhibit requires dbus and
# dbus-user-session to be installed.
ExecStart=systemd-inhibit --who="borgmatic-%i" --why="Prevent interrupting backup of %I" /usr/local/bin/borgmatic -c /etc/borgmatic/%i.yaml --syslog-verbosity 1

ExecStopPost=/usr/local/bin/restart-compose-after-backup.sh %i
</file>

You have to use a script to restart the compose setup when the service is finished:
<file bash /usr/local/bin/restart-compose-after-backup.sh>
#!/bin/bash
systemctl -q is-enabled "docker-compose@$1.service" && systemctl start "docker-compose@$1.service"
exit 0
</file>

And the corresponding systemd timer looks like that:
<file ini /etc/systemd/system/borgmatic-compose-nightly@.timer>
[Unit]
Description=%j backups for docker-compose service %i

[Timer]
Unit=borgmatic-compose@%i.service
OnCalendar=*-*-* 03:15:00
RandomizedDelaySec=15min

[Install]
WantedBy=timers.target
</file>