From 5bdbcea22a55979bcd4aa21aa4f76c9b818e1511 Mon Sep 17 00:00:00 2001
From: root
Date: Wed, 17 May 2017 04:06:27 +0200
Subject: Add backup scripts

---
 backup-all.sh     | 24 ++++++++++++++++++++++++
 backup-dataset.sh | 27 +++++++++++++++++++++++++++
 snap.sh           | 45 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 96 insertions(+)
 create mode 100755 backup-all.sh
 create mode 100755 backup-dataset.sh
 create mode 100755 snap.sh

diff --git a/backup-all.sh b/backup-all.sh
new file mode 100755
index 0000000..aeea10b
--- /dev/null
+++ b/backup-all.sh
@@ -0,0 +1,24 @@
+#!/bin/sh -euf
+
+usage() (
+	echo "backup-all.sh <dataset list> [duplicity options]"
+	echo
+	echo "Backups each dataset listed in the given file using Duplicity,"
+	echo "each line of the file being a pair of a dataset name and a Duplicity destination URI."
+	echo
+)
+
+backup_all() (
+	LIST_FILE="$1"
+	DUPLICITY_OPTIONS="$2"
+
+	while read -r LINE; do
+		backup-dataset.sh $LINE $DUPLICITY_OPTIONS
+	done <"$LIST_FILE"
+)
+
+case "${1:-help}" in
+	"help")	usage;;
+	*)	backup_all "$1" "${2:-}";;
+esac
+
diff --git a/backup-dataset.sh b/backup-dataset.sh
new file mode 100755
index 0000000..e4303c5
--- /dev/null
+++ b/backup-dataset.sh
@@ -0,0 +1,27 @@
+#!/bin/sh -euf
+
+SNAPSHOT_DIRECTORY="/var/backups/dataset-snapshots"
+
+usage() (
+	echo "backup-dataset.sh <dataset> <duplicity destination> [duplicity options]"
+	echo
+	echo "Performs a duplicity incremental backup of the specified dataset."
+	echo "An atomic snapshot of the dataset is taken prior to backing up."
+	echo
+)
+
+backup_dataset() (
+	DATASET="$1"
+	DESTINATION="$2"
+	DUPLICITY_OPTIONS="$3"
+
+	sudo snap.sh snap "$DATASET"
+	PASSPHRASE="null" duplicity $DUPLICITY_OPTIONS "$SNAPSHOT_DIRECTORY/$DATASET" "$DESTINATION"
+	sudo snap.sh free "$DATASET"
+)
+
+case "${1:-help}" in
+	"help")	usage;;
+	*)	backup_dataset "$1" "$2" "${3:-}";;
+esac
+
diff --git a/snap.sh b/snap.sh
new file mode 100755
index 0000000..36f32e6
--- /dev/null
+++ b/snap.sh
@@ -0,0 +1,45 @@
+#!/bin/sh -euf
+
+MOUNT_DIRECTORY="/var/backups/dataset-snapshots"
+SNAPSHOT_LABEL="snap"
+
+usage() (
+	echo "snap.sh <snap|free> <dataset>"
+	echo
+	echo "Creates or destroys a snapshot of a ZFS dataset, labelled with @$SNAPSHOT_LABEL."
+	echo "Snapshots are automatically mounted in $MOUNT_DIRECTORY."
+	echo "If a snapshot already exists, it is replaced."
+	echo
+)
+
+create_snapshot() (
+	DATASET="$1"
+
+	SNAPSHOT_NAME="$DATASET@$SNAPSHOT_LABEL"
+	SNAPSHOT_DIRECTORY="$MOUNT_DIRECTORY/$DATASET"
+
+	if zfs list "$SNAPSHOT_NAME" >/dev/null 2>/dev/null; then
+		echo "Snapshot already exists. Overwriting."
+		destroy_snapshot "$DATASET"
+	fi
+
+	zfs snapshot "$SNAPSHOT_NAME"
+	mkdir -p "$SNAPSHOT_DIRECTORY"
+	mount -t zfs "$SNAPSHOT_NAME" "$SNAPSHOT_DIRECTORY"
+)
+
+destroy_snapshot() (
+	DATASET="$1"
+
+	SNAPSHOT_NAME="$DATASET@$SNAPSHOT_LABEL"
+
+	umount "$SNAPSHOT_NAME" 2>/dev/null || true
+	zfs destroy "$SNAPSHOT_NAME"
+)
+
+case "${1:-help}" in
+	"help")	usage;;
+	"snap")	create_snapshot "$2";;
+	"free")	destroy_snapshot "$2";;
+esac
+
-- 
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