diff --git a/script/host/zfs/composition-sync/sync-send.sh b/script/host/zfs/composition-sync/sync-send.sh
new file mode 100755
index 0000000..b20782a
--- /dev/null
+++ b/script/host/zfs/composition-sync/sync-send.sh
@@ -0,0 +1,122 @@
+#!/bin/bash
+
+function printFoundCommonSnapshot() {
+    local _ZFS _COMMON_SNAPSHOT_CANDIDATE
+    _ZFS="${1:?"printFoundCommonSnapshot(): Missing first parameter ZFS"}"
+    _COMMON_SNAPSHOT_CANDIDATE="${2:?"printFoundCommonSnapshot(): Missing second parameter COMMON_SNAPSHOT_CANDIDATE"}"
+    readonly _ZFS _COMMON_SNAPSHOT_CANDIDATE
+
+    local _FOUND_COMMON_SNAPSHOT
+    _FOUND_COMMON_SNAPSHOT=""
+
+    while read -r _ROW
+    do
+        if [ "${_ROW}" == "${_ZFS}@${_COMMON_SNAPSHOT_CANDIDATE}" ]; then
+            _FOUND_COMMON_SNAPSHOT="${_ROW}"
+            break
+        fi
+    done < <(zfs list -H -o name -S creation -t snapshot "${_ZFS}")
+
+    [ $? -eq 0 ] \
+        && echo "${_FOUND_COMMON_SNAPSHOT}" \
+        && return 0
+
+    return 1
+}
+
+function removeAllSyncSnapshotsExeptTheCommonOne() {
+    local _ZFS _RECEIVERHOST _COMMON_SNAPSHOT
+    _ZFS="${1:?"removeAllSyncSnapshotsExeptTheCommonOne(): Missing first parameter ZFS"}"
+    _RECEIVERHOST="${2:?"removeAllSyncSnapshotsExeptTheCommonOne(): Missing second parameter RECEIVERHOST"}"
+    _COMMON_SNAPSHOT="${3:?"removeAllSyncSnapshotsExeptTheCommonOne(): Missing third parameter COMMON_SNAPSHOT"}"
+    readonly _ZFS _RECEIVERHOST _COMMON_SNAPSHOT
+
+    while read -r _ROW
+    do
+        # Skip the common snapshot to keep it.
+        # If the common snapshot is not a sync-snapshot all sync-snapshots will be removed.
+        if [ "${_ROW}" == "${_COMMON_SNAPSHOT}" ]; then
+            continue
+        fi
+        # Destroy all remaining sync-snapshots of the receiving host
+        zfs destroy "${_ROW}"
+    done < <(zfs list -H -o name -S creation -t snapshot "${_ZFS}" | grep -E "^${_ZFS}@SYNC_${_RECEIVERHOST}_")
+}
+
+function sendResume() {
+    local _RESUME_TOKEN
+    _RESUME_TOKEN="${1:?"sendResume(): Missing first parameter RESUME_TOKEN"}"
+    readonly _RESUME_TOKEN
+
+    zfs send -t "${RESUME_TOKEN}" \
+        && return 0
+
+    return 1
+}
+
+function isValid() {
+    # printf '%s'
+    #  - always treats the contents of ${1} as pure plain text.
+    # grep -qE: checks RegExp, but quiet
+    printf '%s' "${1}" | grep -qE "${2:?"isValid(): Missing REGEXP"}"
+}
+
+function isValidOptional() {
+    [ -z "${1}" ] || isValid "${1}" "${2}"
+}
+
+
+
+# Parameter 1: Only alphanumeric characters allowed and [._-]  if not leading (due to: -oProxyCommand=...).
+# Parameter 2: Only alphanumeric characters allowed and [.-]   if not leading (due to: -oProxyCommand=...).
+# Parameter 3: Only alphanumeric characters allowed and [._:-] if not leading (due to: -oProxyCommand=...), but can be empty.
+# Parameter 4: Only alphanumeric characters allowed and [._:-] if not leading (due to: -oProxyCommand=...), but can be empty.
+if isValid "${1:?"RECEIVERHOST missing"}" '^[a-zA-Z0-9][a-zA-Z0-9._-]*$' \
+    && isValid "${2:?"COMPOSITION missing"}" '^[a-zA-Z0-9][a-zA-Z0-9.-]*$' \
+    && isValidOptional "${3}" '^[a-zA-Z0-9][a-zA-Z0-9._:-]*$' \
+    && isValidOptional "${4}" '^[a-zA-Z0-9][a-zA-Z0-9._:-]*$'
+then
+    _RECEIVERHOST="${1}"
+    _COMPOSITION="${2}"
+    _RECEIVERS_SNAPSHOT="${3}"
+    _RESUME_TOKEN="${4}"
+
+    _ZFS="zpool1/persistent/${_COMPOSITION:?"COMPOSITION missing"}"
+
+    # Resume mode
+    if [ "${_RECEIVERS_SNAPSHOT}" == "RESUME" ]; then
+        sendResume "${_RESUME_TOKEN}"
+        exit $?
+    fi
+
+    # This common snapshot is the starting-point, if available.
+    _COMMON_SNAPSHOT="$(printFoundCommonSnapshot ${_ZFS} ${_RECEIVERS_SNAPSHOT})"
+
+    [ "${_COMMON_SNAPSHOT}" == "" ] \
+        && [ "${_RECEIVERS_SNAPSHOT}" != "" ] \
+        && echo "Requested snapshot '${_RECEIVERS_SNAPSHOT}' not available" \
+        && exit 1
+
+    [ "${_COMMON_SNAPSHOT}" != "" ] \
+        && removeAllSyncSnapshotsExeptTheCommonOne "${_ZFS}" "${_RECEIVERHOST}" "${_COMMON_SNAPSHOT}"
+
+    # Now create the first or a further sync-snapshot as end-point.
+    _NEW_SNAPSHOT="${_ZFS}@SYNC_${_RECEIVERHOST:?"RECEIVERHOST missing"}_$(date -u "+%Y-%m-%d_%H:%M:%S")"
+
+    [ "${_COMMON_SNAPSHOT}" == "" ] \
+        && zfs snapshot "${_NEW_SNAPSHOT}" \
+        && zfs send -c -R "${_NEW_SNAPSHOT}" \
+        && exit 0
+
+    [ "${_COMMON_SNAPSHOT}" != "" ] \
+        && removeAllSyncSnapshotsExeptTheCommonOne "${_ZFS}" "${_RECEIVERHOST}" "${_COMMON_SNAPSHOT}" \
+        && zfs snapshot "${_NEW_SNAPSHOT}" \
+        && zfs send -c -R -I "${_COMMON_SNAPSHOT}" "${_NEW_SNAPSHOT}" \
+        && exit 0
+
+else
+    echo "Failure: At least one parameter is invalid" >&2
+    exit 1
+fi
+
+exit 1
diff --git a/script/host/zfs/composition-sync/sync.sh b/script/host/zfs/composition-sync/sync.sh
new file mode 100755
index 0000000..fad2c6c
--- /dev/null
+++ b/script/host/zfs/composition-sync/sync.sh
@@ -0,0 +1,201 @@
+#!/bin/bash
+
+_MODE=$(echo "${1:?"MODE missing [--all, --once, --loop]"}" | sed -E 's|[^a-zA-Z0-9_-]*||g')
+_COMPOSITION=$(echo "${2}" | sed -E 's|[^a-zA-Z0-9_-]*||g')
+_SSH_PORT=$(echo "${3:-22}" | sed -E 's/[^0-9]//g')
+
+# Folders always ends with an tailing '/'
+_SCRIPT="$(readlink -f "${0}" 2> /dev/null)"
+_CIS_ROOT="${_SCRIPT%/script/host/zfs/composition-sync/sync.sh}/"  #Removes shortest matching pattern '/script/host/zfs/composition-sync/sync.sh' from the end
+_SEND_SCRIPT="${_CIS_ROOT:?"Missing CIS_ROOT"}script/host/zfs/composition-sync/sync-send.sh"
+_DOMAIN="$("${_CIS_ROOT:?"Missing CIS_ROOT"}core/printOwnDomain.sh")"
+_DEFINITIONS="${_CIS_ROOT:?"Missing CIS_ROOT"}definitions/${_DOMAIN:?"Missing DOMAIN"}/"
+
+_RECEIVERHOST=$(hostname -b)
+
+function stopObsoleteScreenSession() {
+    local _RECEIVERHOST _SYNCHOSTS_FILE _SCREEN_SESSION _COMPOSITION _PID
+    _RECEIVERHOST="${1:?"stopObsoleteScreenSession(): Missing first parameter RECEIVERHOST"}"
+    _SYNCHOSTS_FILE="${2:?"stopObsoleteScreenSession(): Missing second parameter SYNCHOSTS_FILE"}"
+    _SCREEN_SESSION="${3:?"stopObsoleteScreenSession(): Missing third parameter SCREEN_SESSION"}"
+    _COMPOSITION=$(echo "$_SCREEN_SESSION" | grep -oE "[^.]+$")
+    _PID=$(echo "$_SCREEN_SESSION" | grep -oE "^[0-9]+")
+    readonly _RECEIVERHOST _SYNCHOSTS_FILE _SCREEN_SESSION _COMPOSITION _PID
+
+    ! grep -qiE "^${_RECEIVERHOST}$" "${_DEFINITIONS}compositions/${_COMPOSITION}/${_SYNCHOSTS_FILE}" \
+        && echo "Stopping screen session of composition-sync: ${_COMPOSITION}" \
+        && screen -XS "${_PID}" quit
+}
+
+function cleanSessions() {
+    local _RECEIVERHOST _SYNCHOSTS_FILE
+    _RECEIVERHOST="${1:?"cleanSessions(): Missing first parameter RECEIVERHOST"}"
+    _SYNCHOSTS_FILE="${2:?"cleanSessions(): Missing second parameter SYNCHOSTS_FILE"}"
+    readonly _RECEIVERHOST _SYNCHOSTS_FILE
+
+    screen -ls | grep -oE "[0-9]+\.compositionsync\.[a-zA-Z0-9_-]+" | while read -r _SCREEN_SESSION; do
+        stopObsoleteScreenSession "${_RECEIVERHOST}" "${_SYNCHOSTS_FILE}" "${_SCREEN_SESSION}"
+    done
+}
+
+function startMissingScreenSession() {
+    local _COMPOSITION _SSH_PORT
+    _COMPOSITION="${1:?"startMissingScreenSession(): Missing first parameter COMPOSITION"}"
+    _SSH_PORT="${2:-22}"
+    readonly _COMPOSITION _SSH_PORT
+
+    ! screen -ls | grep -qoE "[0-9]+\.compositionsync\.${_COMPOSITION}" \
+        && echo "Starting screen session of composition-sync: ${_COMPOSITION}" \
+        && screen -dmS "compositionsync.${_COMPOSITION}" "${_SCRIPT}" --loop "${_COMPOSITION}" "${_SSH_PORT}"
+}
+
+function addSessions() {
+    local _RECEIVERHOST _SYNCHOSTS_FILE
+    _RECEIVERHOST="${1:?"addSessions(): Missing first parameter RECEIVERHOST"}"
+    _SYNCHOSTS_FILE="${2:?"addSessions(): Missing second parameter SYNCHOSTS_FILE"}"
+    readonly _RECEIVERHOST _SYNCHOSTS_FILE
+
+    local _COMPOSITION
+    grep -lrE "^${_RECEIVERHOST}" ${_DEFINITIONS}compositions/*/${_SYNCHOSTS_FILE} | while read -r _CURRENT_SYNCHOSTS_FILE; do
+        _SSH_PORT=$(grep -E "^${_RECEIVERHOST} usePort [0-9]*.*$" "${_CURRENT_SYNCHOSTS_FILE}" | cut -d' ' -f3 | xargs)
+        _COMPOSITION=$(basename $(dirname "${_CURRENT_SYNCHOSTS_FILE}"))
+        startMissingScreenSession "${_COMPOSITION}" "${_SSH_PORT}"
+    done
+}
+
+function destroySyncSnapshot() {
+    local _ZFS _SNAPSHOT
+    _ZFS="${1:?"destroySyncSnapshot(): Missing first parameter ZFS"}"
+    _SNAPSHOT="${2}"
+    readonly _ZFS _SNAPSHOT
+
+    # Nothing to do
+    [ -z "${_SNAPSHOT}" ] && return 0
+
+    echo "${_SNAPSHOT}" | grep -qF "${_ZFS:?"destroySyncSnapshot(): Missing ZFS"}@SYNC" \
+        && zfs destroy "${_SNAPSHOT}" \
+        && return 0
+
+    return 1
+}
+
+function protectZFS() {
+    local _ZFS
+    _ZFS="${1:?"protectZFS(): Missing first parameter ZFS"}"
+    readonly _ZFS
+
+    zfs set readonly=on "${_ZFS}"
+    zfs set mountpoint=none "${_ZFS}"
+
+    return 0
+}
+
+function removeForeignSyncSnapshots() {
+    local _RECEIVERHOST _ZFS
+    _RECEIVERHOST="${1:?"removeForeignSyncSnapshots(): Missing first parameter RECEIVERHOST"}"
+    _ZFS="${2:?"removeForeignSyncSnapshots(): Missing second parameter ZFS"}"
+    readonly _RECEIVERHOST _ZFS
+
+    zfs list -t snapshot -H -o name "${_ZFS}" | grep -- "${_ZFS}@SYNC" | grep -v -i "@SYNC_${_RECEIVERHOST}_" | while read _SNAP; do
+    echo -n "Removing foreign snapshot:  ${_SNAP} ... " \
+        && destroySyncSnapshot "${_ZFS}" "${_SNAP}" \
+        && echo "done"
+    done
+
+    return 0
+}
+
+function removeOutdatedSyncSnapshots() {
+    local _RECEIVERHOST _ZFS _NEWEST_SNAPSHOT
+    _RECEIVERHOST="${1:?"removeOutdatedSyncSnapshots(): Missing first parameter RECEIVERHOST"}"
+    _ZFS="${2:?"removeOutdatedSyncSnapshots(): Missing second parameter ZFS"}"
+    _NEWEST_SNAPSHOT=$(zfs list -H -o name -S name -t snapshot "${_ZFS}" | grep -E "^${_ZFS}@SYNC_${_RECEIVERHOST}_" | head -n 1)
+    readonly _RECEIVERHOST _ZFS _NEWEST_SNAPSHOT
+
+    # Nothing to do, because if there is no newest snapshot then there cannot be anyone
+    [ -z "${_NEWEST_SNAPSHOT}" ] && return 0
+
+    # Remove all but the newest snapshot, which is the common snapshot in the next run
+    zfs list -t snapshot -H -o name "${_ZFS}" | grep -- "${_ZFS}@SYNC_${_RECEIVERHOST}_" | grep -v -i "${_NEWEST_SNAPSHOT}" | while read _SNAP; do
+    echo -n "Removing outdated snapshot: ${_SNAP} ... " \
+        && destroySyncSnapshot "${_ZFS}" "${_SNAP}" \
+        && echo "done"
+    done
+
+    return 0
+}
+
+function receive() {
+    local _RECEIVERHOST _COMPOSITION
+    _RECEIVERHOST="${1:?"receive(): Missing first parameter RECEIVERHOST"}"
+    _COMPOSITION="${2:?"receive(): Missing second parameter COMPOSITION"}"
+    readonly _RECEIVERHOST _COMPOSITION
+
+    (
+        flock -n 9 || exit 1
+
+        _SOURCEHOST=$(cat ${_DEFINITIONS}compositions/${_COMPOSITION}/current-host)
+
+        _ZFS="zpool1/persistent/${_COMPOSITION}-BACKUP"
+        _SSH_COMMAND="ssh -p ${_SSH_PORT} -o ConnectTimeout=20 -o ServerAliveInterval=15 -C composition-sync@${_SOURCEHOST}"
+
+        _COMMON_SNAPSHOT=""
+        _RESUME_TOKEN=$(zfs get -H -o value receive_resume_token "${_ZFS}" 2> /dev/null)
+        if [ -n "${_RESUME_TOKEN}" ] && [ "${_RESUME_TOKEN}" != "-" ]; then
+            echo "Resume token present trying to resume at ${_RESUME_TOKEN}"
+            _COMMON_SNAPSHOT="RESUME"
+        else
+            _RESUME_TOKEN=""
+            _COMMON_SNAPSHOT=$(zfs list -H -o name -S creation -t snapshot "${_ZFS}" 2> /dev/null | head -n 1)
+            ! [ -z "${_COMMON_SNAPSHOT}" ] \
+                && echo "Rolling back to newest snapshot: ${_COMMON_SNAPSHOT}" \
+                && zfs rollback -r "${_COMMON_SNAPSHOT}"
+        fi
+
+        # Add "-s" for resumable streams in the next line at zfs receive. Not done yet because of: cannot receive resume stream: kernel modules must be upgraded to receive this stream.
+        ${_SSH_COMMAND} "sudo ${_SEND_SCRIPT:?"Missing SEND_SCRIPT"} \"${_RECEIVERHOST}\" \"${_COMPOSITION}\" \"${_COMMON_SNAPSHOT#${_ZFS}@}\" \"${_RESUME_TOKEN}\"" | zfs receive -v "${_ZFS}"
+        [ $? -ne 0 ] \
+            && echo "Unable to receive stream unsing these settings:" \
+            && echo "  - Sending host:     ${_SOURCEHOST}:${_SSH_PORT}" \
+            && echo "  - Receiving host:   ${_RECEIVERHOST}" \
+            && echo "  - Composition:      ${_COMPOSITION}" \
+            && echo "  - Offered snapshot: ${_COMMON_SNAPSHOT}" \
+            && echo "  - Resume token:     ${_RESUME_TOKEN}" \
+            && return 1
+
+        protectZFS "${_ZFS}"
+        removeForeignSyncSnapshots "${_RECEIVERHOST}" "${_ZFS}"
+        removeOutdatedSyncSnapshots "${_RECEIVERHOST}" "${_ZFS}"
+
+    ) 9>>/tmp/synccomposition.${_COMPOSITION}.lock
+
+    [ $? -eq 0 ] && return 0
+
+    return 1
+}
+
+
+
+[ "${_MODE}" == "--all" ] \
+    && cleanSessions "${_RECEIVERHOST}" composition-sync-hosts \
+    && addSessions "${_RECEIVERHOST}" composition-sync-hosts \
+    && exit 0
+
+[ "${_MODE}" == "--once" ] \
+    && receive "${_RECEIVERHOST}" "${_COMPOSITION}" \
+    && exit 0
+
+[ "${_MODE}" == "--loop" ] && while true; do
+    receive "${_RECEIVERHOST}" "${_COMPOSITION}" \
+        && echo "Sleep for 5s" \
+        && sleep 5 \
+        && echo \
+        && continue
+
+    echo
+    echo "Waiting 5min then ABORT!"
+    sleep 300
+    break
+done
+
+exit 1
diff --git a/script/host/zfs/diff.sh b/script/host/zfs/diff.sh
new file mode 100755
index 0000000..98e3fdf
--- /dev/null
+++ b/script/host/zfs/diff.sh
@@ -0,0 +1,118 @@
+#!/bin/bash
+
+if [ "$#" -lt 2 ]; then
+    echo "Compares the difference of two snapshots of the same dataset."
+    echo "If a file was modified, but has the same content, it will be skipped."
+    echo "Remaining files can be analysed more deeply using --singlefile mode."
+    echo
+    echo "Usage:"
+    echo "  - $0 <dataset>@<snap1> <dataset>@<snap2> [M+-]                  # scans files, default is modified only [M]"
+    echo "  - $0 <dataset>@<snap1> <dataset>@<snap2> --singlefile [path]    # deeper look at one file's differences"
+    exit 1
+fi
+
+SNAP1_FULL=$1
+SNAP2_FULL=$2
+TYPES_FILTER=${3:-M}
+TARGET_PATH=$4
+
+DATASET=${SNAP1_FULL%@*}
+SNAP1_NAME=${SNAP1_FULL#*@}
+SNAP2_NAME=${SNAP2_FULL#*@}
+
+MOUNTPOINT=$(zfs get -H -o value mountpoint "$DATASET")
+
+if [ "$MOUNTPOINT" == "none" ] || [ ! -d "$MOUNTPOINT" ]; then
+    echo "Failure: dataset is not accessable via its mountpoint."
+    exit 1
+fi
+
+[ "${#TYPES_FILTER}" -gt 3 ] && [ "$TYPES_FILTER" != "--singlefile" ] \
+    && [ -n "$TARGET_PATH"] \
+    && echo "Failure: Mode ${TYPES_FILTER} unknown." \
+    && exit 1
+
+[ "$TYPES_FILTER" == "--singlefile" ] \
+    && [ -z "$TARGET_PATH"] \
+    && echo "Failure: Mode --singlefile requires path." \
+    && exit 1
+
+
+
+if [ "$TYPES_FILTER" == "--singlefile" ] && [ -n "$TARGET_PATH" ]; then
+    rel_path=${TARGET_PATH#$MOUNTPOINT/}
+    file1="$MOUNTPOINT/.zfs/snapshot/$SNAP1_NAME/$rel_path"
+    file2="$MOUNTPOINT/.zfs/snapshot/$SNAP2_NAME/$rel_path"
+
+    echo "Vergleiche: $rel_path"
+    echo "Snapshot 1: $file1"
+    echo "Snapshot 2: $file2"
+    echo "--------------------------------------------------------"
+
+    if [ ! -f "$file1" ] && [ ! -f "$file2" ]; then
+        echo "Fehler: Datei existiert in beiden Snapshots nicht."
+        exit 1
+    fi
+
+    # Standard Diff (meldet 'Binary files differ' bei Binärdateien)
+    diff -u "$file1" "$file2"
+
+    # Alternativ: vimdiff (einfach die obere Zeile auskommentieren und hier das # entfernen)
+    # vimdiff "$file1" "$file2"
+
+    exit 0
+fi
+
+
+
+echo -e "Diff(Bytes)\tPfad"
+echo -e "--------------------------------------------------------"
+
+zfs diff -H "$SNAP1_FULL" "$SNAP2_FULL" | while IFS=$'\t' read -r type path; do
+
+    if [[ ! "$TYPES_FILTER" == *"$type"* ]]; then
+        continue
+    fi
+
+    rel_path=${path#$MOUNTPOINT/}
+    file1="$MOUNTPOINT/.zfs/snapshot/$SNAP1_NAME/$rel_path"
+    file2="$MOUNTPOINT/.zfs/snapshot/$SNAP2_NAME/$rel_path"
+
+    case "$type" in
+        "M")
+            if [ -f "$file1" ] && [ -f "$file2" ]; then
+                read -r size1 mtime1 < <(stat -c "%s %Y" "$file1")
+                read -r size2 mtime2 < <(stat -c "%s %Y" "$file2")
+                diff_val=$((size2 - size1))
+
+                if [ "$diff_val" -eq 0 ]; then
+                    [ "$mtime1" == "$mtime2" ] && continue
+                    hash_line1=$(sha1sum "$file1")
+                    sha1_1=${hash_line1%% *}
+                    hash_line2=$(sha1sum "$file2")
+                    sha1_2=${hash_line2%% *}
+                    [ "$sha1_1" == "$sha1_2" ] && continue
+                    echo -e "0\t\t${path}"
+                else
+                    echo -e "${diff_val}\t\t${path}"
+                fi
+            fi
+            ;;
+        "+")
+            if [ -f "$file2" ]; then
+                size2=$(stat -c%s "$file2")
+                echo -e "+${size2}\t\t${path}"
+            fi
+            ;;
+        "-")
+            if [ -f "$file1" ]; then
+                size1=$(stat -c%s "$file1")
+                echo -e "-${size1}\t\t${path}"
+            fi
+            ;;
+    esac
+done
+
+echo -e "--------------------------------------------------------"
+echo -e "Use the following command for a deeper look at one file:"
+echo -e "$0 $1 $2 --singlefile [Pfad]"