From 33b1bd70f2c69f8d3b9ac2e94ccc4ab86f5dc058 Mon Sep 17 00:00:00 2001
From: tdpeuter <tibo.depeuter@gmail.com>
Date: Sat, 7 Oct 2023 11:06:10 +0200
Subject: [PATCH] Add ZFS dataset backup script #1 and #22

---
 scripts/backup-zfs-dataset.sh | 122 ++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100755 scripts/backup-zfs-dataset.sh

diff --git a/scripts/backup-zfs-dataset.sh b/scripts/backup-zfs-dataset.sh
new file mode 100755
index 0000000..f93cbf3
--- /dev/null
+++ b/scripts/backup-zfs-dataset.sh
@@ -0,0 +1,122 @@
+#!/bin/bash
+# Create archived backups of zfs datasets, with support for incremental backups from automated snapshots.
+# Usage: backup-zfs-dataset [OPTIONS] <dataset>
+
+usage() {
+    >&2 printf "Usage: %s [OPTIONS] <dataset>\n" "$0"
+    >&2 printf "Options:\n"
+    >&2 printf "\t-c  --compression-level <level>       \t Specify compression level (integer)\n"
+    >&2 printf "\t-s  --dataset <dataset name>          \t Specify dataset name\n"
+    >&2 printf "\t-d  --destination <path to directory> \t Specify destination\n"
+    >&2 printf "\t-m  --max-size <size>                 \t Specify maximum size of archive parts\n"
+    exit "${1:-1}"
+}
+
+# Get options.
+
+while [[ $# -gt 0 ]]; do
+    case "${1}" in
+        --compression_level | -c)
+            if ! [[ "${2}" =~ -[[:digit:]] ]]; then
+                >&2 printf "Error: Invalid compression level: %s\n" "${2}"
+                usage
+            fi
+            compression_level="${2}"
+            shift 2
+            ;;
+        --dataset | -s)
+            if ! [ -n "${2}" ]; then
+                >&2 printf "Error: Invalid dataset: %s\n" "${2}"
+                usage
+            fi
+            dataset="${2}"
+            shift 2
+            ;;
+        --destination | -d)
+            if ! [ -d "${2}" ]; then
+                >&2 printf "Error: Destination directory does not exist: %s\n" "${2}"
+                usage
+            fi
+            destination="${2}"
+            shift 2
+            ;;
+        --max-size | -m)
+            if ! [[ "${2}" =~ [[:digit:]](K|M|G) ]]; then
+                >&2 printf "Error: Invalid maximum size: %s\n" "${2}"
+                usage
+            fi
+            max_size="${2}"
+            shift 2
+            ;;
+        *)
+            >&2 printf "Error: Invalid option: %s\n" "${1}"
+            usage
+            ;;
+    esac
+done
+
+# Check arguments.
+
+if [ -z "${dataset}" ]; then
+    >&2 printf "Error: You need to specify a dataset.\n"
+    usage
+fi
+
+# Working snapshots
+
+# Find snapshots
+snapshot_location="/mnt/${dataset}/.zfs/snapshot"
+latest_auto="$( find "${snapshot_location}"/* -maxdepth 0 -name 'auto*' -type d | sort -n | tail -n1 | xargs -n1 basename >2 /dev/null )"
+latest_manual="$( find "${snapshot_location}"/* -maxdepth 0 -name 'manual*' -type d | sort -n | tail -n1 | xargs -n1 basename >2 /dev/null )"
+
+# Check snapshots existance
+if ! [ -n "${latest_manual}" ]; then
+    >&2 printf "Error: No manual snapshot could be found!\n"
+    exit 2
+fi
+if ! [ -n "${latest_auto}" ]; then
+    >&2 printf "Error: No automatic snapshot could be found!\n"
+    exit 2
+fi
+
+printf "Latest auto snapshot: %s\nLatest manual snapshot: %s\n" "${latest_auto}" "${latest_manual}"
+
+# Abort entire script if anything fails.
+set -e
+
+# Backups
+
+# Base backup.
+output_filename="${destination}/${latest_manual}.gz"
+existing_backup="$( find "${destination}" -type f -name "${output_filename}.part.[a-z][a-z]" -print )" # -quit if you don't need to know every file.
+if ! [ ${existing_backup} ]; then
+    printf "Info: If you've manually created a new snapshot, you might want to remove the old backups.\n"
+    printf "Latest manual snapshot was not yet backed up, backing up now.\n"
+    sudo zfs send --verbose "${dataset}@${latest_manual}" \
+        | gzip "${compression_level:='-1'}" --verbose --rsyncable \
+        | split - --verbose -b "${max_size}" "${output_filename}.part."
+    printf "Written manual backup to: %s\n" "${output_filename}"
+elif [ "${force_create_manual_backup}" ]; then
+    # TODO What if the new backup is smaller than the previous?
+    printf "Removing previous backup files.\n"
+    rm "${existing_backup}"
+    printf "Backing up manual snapshot.\n"
+    sudo zfs send --verbose "${dataset}@${latest_manual}" \
+        | gzip "${compression_level:='-1'}" --verbose --rsyncable \
+        | split - --verbose -b "${max_size}" "${output_filename}.part."
+    printf "Written manual backup to: %s\n" "${output_filename}"
+else
+    printf "Found existing backup of manual snapshot: %s\n" "${existing_backup}"
+fi
+
+# Incremental incremental backup.
+printf "Creating incremental backup between %s and %s\n" "${latest_manual}" "${latest_auto}"
+output_filename="${destination}/${latest_manual}-${latest_auto}.gz"
+sudo zfs send -i "@${latest_manual}" "${dataset}@${latest_auto}" \
+    | gzip "${compression_level}" --verbose \
+    | split - --verbose -b "${max_size:='2G'}" "${output_filename}.part."
+printf "Written incremental backup to: %s\n" "${output_filename}"
+
+# TODO Cleanup
+
+printf "Done!\n"