server/Services/BackupScheduler.cs

@@ -37,11 +37,28 @@ public sealed class BackupScheduler : IDisposable
     public void Start()
     {
         if (string.IsNullOrWhiteSpace(_config.BackupSchedule)) return;
-        if (Parse(_config.BackupSchedule) == default)
+        var parsed = Parse(_config.BackupSchedule);
+        if (parsed == default)
         {
             _log($"[backup-scheduler] Invalid backupSchedule '{_config.BackupSchedule}'. Expected 'HH:mm', 'HH:mm,HH:mm', or 'every Nh'/'every Nm'. Disabled.");
             return;
         }
+
+        // No-replay startup: mark all of today's already-passed slots as fired so
+        // the wake loop only fires future slots. Without this, a daily-times
+        // schedule like "00:00,04:00,...,20:00" on a service restart at 19:00
+        // would catch up by firing 5 backups at 1-minute intervals (one per
+        // missed slot), each producing a full-world zip of the SAME world state.
+        // For full-snapshot backups that's pure waste -- the live world hasn't
+        // diverged across missed slots.
+        if (parsed.Times is not null)
+        {
+            var nowTime = TimeOnly.FromDateTime(DateTime.Now);
+            _lastFireDay = DateOnly.FromDateTime(DateTime.Now);
+            foreach (var t in parsed.Times)
+                if (t <= nowTime) _firedToday.Add(t);
+        }
+
         _cts?.Cancel();
         _cts = new CancellationTokenSource();
         _loop = Task.Run(() => RunAsync(_cts.Token));