Clean old ZFS auto-snapshots on backup destinations

zfs-clean-snapshot

#!/bin/sh

filter_snapshots() {
    echo "$1" | grep $2 | tac | tail -n +$(($3 + 1)) | sed 's/.*@//' | sed -z 's/\n/,/g'
}

if [ $# -ne 6 ]; then
    echo "usage: $0 <dataset> <frequent> <hourly> <daily> <weekly> <monthly>"
    exit 1
fi

for dataset in $(zfs list -r -o name $1 | tail -n +2); do
    printf "\e[32m=> Cleaning up snapshots for $dataset\e[0m\n"

    snapshots=$(zfs list -t snapshot -o name $dataset)

    # Remove “system” snapshots.
    valid_state=$(filter_snapshots "$snapshots" valid-state 0)
    update=$(filter_snapshots "$snapshots" update 0)
    sys_snaps=$valid_state$update

    # Remove manual syncoid snapshots.
    manual_saturne=$(filter_snapshots "$snapshots" syncoid_saturne_2 0)
    manual_helios=$(filter_snapshots "$snapshots" syncoid_helios_2 0)
    manual_nixos=$(filter_snapshots "$snapshots" syncoid_nixos_2 0)
    manual=$manual_saturne$manual_helios$manual_nixos

    # Keep only one syncoid snapshot per backup pool.
    old_helios=$(filter_snapshots "$snapshots" syncoid_helios_saturne 1)
    old_titan=$(filter_snapshots "$snapshots" syncoid_titan_saturne 1)
    old_tethys=$(filter_snapshots "$snapshots" syncoid_tethys_saturne 1)
    old_backup=$old_helios$old_titan$old_tethys

    # Keep auto-snapshots as configured.
    old_frequent=$(filter_snapshots "$snapshots" frequent $2)
    old_hourly=$(filter_snapshots "$snapshots" hourly $3)
    old_daily=$(filter_snapshots "$snapshots" daily $4)
    old_weekly=$(filter_snapshots "$snapshots" weekly $5)
    old_monthly=$(filter_snapshots "$snapshots" monthly $6)
    old_auto=$old_frequent$old_hourly$old_daily$old_weekly$old_monthly

    old_snapshots=$(echo $sys_snaps$manual$old_backup$old_auto | sed 's/.$//')

    if [ "$old_snapshots" != "" ]; then
      zfs destroy -v $dataset@$old_snapshots
    fi
done

thanks you. This is exactly what I was needing!

Hello @rub2012, glad it helped you! I’ve just updated it with the version I am currently using, which adds the following:

• Cleanup manual syncoid snapshots done from a few hosts (you’ll want to update the filters)
• Cleanup syncoid snapshots from other backup pools, keeping 1
• Pass the number of auto-snapshots to keep as arguments
• Optimise the cleanup time by running zfs list -t snapshot only once per dataset