Add backup scripts

3 files changed, 96 insertions, 0 deletions

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
+