zfs-automatic-snapshots/etc/zfs-auto-snapshot.cron.frequent

PATH="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"

*/15 * * * * root command -v zfs-auto-snapshot >/dev/null 2>&1 && exec zfs-auto-snapshot --label quarterhour --keep @KEEP_FREQUENT@