diff --git a/miyagi-backup.sh b/miyagi-backup.sh
index 2f62ec9..5605578 100644
--- a/miyagi-backup.sh
+++ b/miyagi-backup.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
-set -euo pipefail
+set -uo pipefail
 IFS=$'\n\t'
 
 PATH="/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin"
@@ -35,6 +35,11 @@ if [[ -n "${CONFIG_FILE:-}" ]]; then
         exit 1
     fi
 
+if ! bash -n "$CONFIG_FILE"; then
+    log "Syntaxfehler in Konfigurationsdatei $CONFIG_FILE"
+    exit 1
+fi
+
     source "$CONFIG_FILE"
 
     # ==========================
@@ -65,7 +70,8 @@ if [[ -n "${CONFIG_FILE:-}" ]]; then
 
     MISSING_VARS=()
     for var in "${REQUIRED_VARS[@]}"; do
-        if [[ -z "${!var:-}" ]]; then
+        #if [[ -z "${!var:-}" ]]; then
+        if ! declare -p "$var" &>/dev/null || [[ -z "${!var}" ]]; then
             MISSING_VARS+=("$var")
         fi
     done
@@ -328,7 +334,14 @@ main() {
     run_maintenance
     run_scrub_stop_local
     run_scrub_stop_src
-    run_pbs_backup
+
+    if [[ "${BACKUPSERVER,,}" == "yes" ]]; then
+        log "BACKUPSERVER ist aktiviert, führe Backup aus..."
+        run_pbs_backup
+    else
+        log "BACKUPSERVER ist nicht aktiviert (BACKUPSERVER=$BACKUPSERVER), überspringe Backup."
+    fi
+
     run_remote_updates
     run_updates
     shutdown_if_requested