diff --git a/sundynix-shared/bus/bus.go b/sundynix-shared/bus/bus.go
index 94cf78a..fc8fc4d 100644
--- a/sundynix-shared/bus/bus.go
+++ b/sundynix-shared/bus/bus.go
@@ -113,6 +113,7 @@ func (b *Bus) EnsureTaskStream(ctx context.Context) error {
 		Name:     contract.StreamTasks,
 		Subjects: []string{contract.SubjectTasksAll},
 		Storage:  jetstream.FileStorage,
+		Replicas: streamReplicas(),
 	})
 	return err
 }
@@ -341,6 +342,7 @@ func (b *Bus) EnsureStatusStream(ctx context.Context) error {
 		Name:     contract.StreamStatus,
 		Subjects: []string{contract.SubjectTaskStatus},
 		Storage:  jetstream.FileStorage,
+		Replicas: streamReplicas(),
 		MaxAge:   24 * time.Hour, // 状态一天内必被消费，过期回收防无限增长
 	})
 	return err
@@ -399,6 +401,7 @@ func (b *Bus) EnsureEvalStream(ctx context.Context) error {
 		Name:     contract.StreamEval,
 		Subjects: []string{contract.SubjectEval},
 		Storage:  jetstream.FileStorage,
+		Replicas: streamReplicas(),
 		MaxAge:   24 * time.Hour, // 评测一天内必被消费，过期回收防无限增长
 	})
 	return err
@@ -453,6 +456,7 @@ func (b *Bus) EnsureUsageStream(ctx context.Context) error {
 		Name:     contract.StreamUsage,
 		Subjects: []string{contract.SubjectUsage},
 		Storage:  jetstream.FileStorage,
+		Replicas: streamReplicas(),
 		MaxAge:   72 * time.Hour, // 计费留足追赶窗口（网关长时间离线后仍能补齐）
 	})
 	return err
@@ -520,6 +524,7 @@ func (b *Bus) EnsureApprovalStream(ctx context.Context) error {
 		Name:     contract.StreamApprovals,
 		Subjects: []string{contract.SubjectApprovalAll},
 		Storage:  jetstream.FileStorage,
+		Replicas: streamReplicas(),
 		MaxAge:   24 * time.Hour,
 	})
 	return err
@@ -774,6 +779,18 @@ func DrainTimeout() time.Duration {
 	return 30 * time.Second
 }
 
+// streamReplicas 是 JetStream 流/KV 桶的副本数，经 NATS_STREAM_REPLICAS 配置，缺省 1。
+// 单机（单节点 NATS）保持 1；三机/单机多节点集群部署设 3，durable 流才有 Raft quorum 容错
+// （计费/状态/用量/评测/审批/入库回写不会因单节点挂掉而丢）。合法值 1/3/5（Raft 需奇数）。
+func streamReplicas() int {
+	if v := os.Getenv("NATS_STREAM_REPLICAS"); v != "" {
+		if n, err := strconv.Atoi(v); err == nil && (n == 1 || n == 3 || n == 5) {
+			return n
+		}
+	}
+	return 1
+}
+
 // drainWait 停止接新活后，等待在途 WaitGroup 跑完，或 dctx 到期放弃。
 func drainWait(wg *sync.WaitGroup, dctx context.Context) {
 	done := make(chan struct{})
@@ -890,6 +907,7 @@ func (b *Bus) EnsureIngestStream(ctx context.Context) error {
 		Name:     contract.StreamIngest,
 		Subjects: []string{contract.SubjectIngestAll},
 		Storage:  jetstream.FileStorage,
+		Replicas: streamReplicas(),
 		MaxAge:   ingestStreamMaxAge,
 	})
 	return err
@@ -934,7 +952,7 @@ func (b *Bus) ConsumeIngestJobs(ctx context.Context, h IngestHandler) (drain fun
 		// 一篇几十万字含切块+上千次 embedding+至多 60 次图谱抽取，可达数分钟；
 		// AckWait 须覆盖单篇最长入库时长，否则在途未 ack 会被重投成重复入库。
 		AckWait:       ingestAckWait(),
-		MaxAckPending: concurrency, // 背压：服务端不下发超过本节点同时能处理的量
+		MaxAckPending: concurrency,      // 背压：服务端不下发超过本节点同时能处理的量
 		MaxDeliver:    ingestMaxDeliver, // 毒消息兜底：重投上限，避免坏作业无限循环
 	})
 	if err != nil {
@@ -1002,9 +1020,10 @@ type KVHandle struct{ kv jetstream.KeyValue }
 // 决定到达即恢复；TTL 兜底清理被遗弃的中断（如审批人始终不处理）。
 func (b *Bus) Checkpoints(ctx context.Context, bucket string, ttl time.Duration) (*KVHandle, error) {
 	kv, err := b.js.CreateOrUpdateKeyValue(ctx, jetstream.KeyValueConfig{
-		Bucket:  bucket,
-		Storage: jetstream.FileStorage,
-		TTL:     ttl,
+		Bucket:   bucket,
+		Storage:  jetstream.FileStorage,
+		Replicas: streamReplicas(),
+		TTL:      ttl,
 	})
 	if err != nil {
 		return nil, fmt.Errorf("kv bucket %q: %w", bucket, err)