---
title: "ZFS Automatic Snapshotting"
date: 2022-10-31T17:56:35Z
tags: ["archlinux", "linux", "zfs"]
draft: true
icon: backup
---

## Goal

## Solution
### Creating snapshots
{{< codegroup >}}
Systemd-timer
```
[Unit]
Description=Create a daily ZFS snapshot for %I

[Timer]
OnCalendar=daily
Persistent=true

[Install]
WantedBy=timers.target
```
---
Systemd-service
```
[Unit]
Description=Create a ZFS snapshot for %I
DefaultDependencies=no

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/bin/bash -c '/usr/bin/zfs snapshot "%I@daily-$(date "+%%Y-%%m-%%d")"'
```
{{< /codegroup >}}

### Cleaning up snapshots
Get all older snapshots
{{< codegroup >}}
bash
```
zfs list -t snapshot -o name | \
perl -e '
my $one_week_ago = `date --date "7 days ago" "+%s"`;
my %snapshots = ();

for (<>) {
    if (my ($dataset, $snapshot, $date) = /([\w\/]+)@(daily-(\d+\-\d+\-\d+))/) {
        if (`date --date "$date" "+%s"` < $one_week_ago) {
            push(@{$snapshots{$dataset}}, $snapshot);
        }
    }
}

while(my ($key, $value) = each %snapshots) {
    print "$key@", join(",", @{$value}), "\n";
}'
```
{{< /codegroup >}}