# Restic to a second disk, the boring way

Published 2026-08-30 · restic, backups, systemd, Linux · https://home.tigran.manukyan.dev/notes/restic-systemd-timer.html

**TL;DR:** Run restic backups from a systemd service and timer (OnCalendar, RandomizedDelaySec, Persistent=true) with `restic forget --prune` retention, credentials in an EnvironmentFile, and a monthly test restore.

I tried a few backup tools with web UIs, then went back to restic and a systemd timer. The only backup that works is the one that runs without me.

## Service

```
# /etc/systemd/system/restic-backup.service
[Unit]
Description=restic backup

[Service]
Type=oneshot
EnvironmentFile=/etc/restic/env
ExecStart=/usr/bin/restic backup /etc /home /srv --exclude-caches
ExecStartPost=/usr/bin/restic forget --keep-daily 7 --keep-weekly 4 --keep-monthly 6 --prune
```

`/etc/restic/env` holds `RESTIC_REPOSITORY` and `RESTIC_PASSWORD_FILE`. Make it `chmod 600`.

## Timer

```
# /etc/systemd/system/restic-backup.timer
[Timer]
OnCalendar=*-*-* 03:30
RandomizedDelaySec=20m
Persistent=true

[Install]
WantedBy=timers.target
```

`Persistent=true` runs a missed backup at the next boot, which matters for a machine that is sometimes off at 3:30.

## The part people skip

Once a month, restore one random file somewhere else and open it. `restic check --read-data-subset=5%` is good too, but it doesn't tell you whether you can find the file you actually need.