feat(backup): 备份/恢复异步化，解决 504 超时

POST /backups 和 POST /backups/:id/restore 改为异步：立即返回 HTTP 202，
后台 goroutine 独立执行 pg_dump → gzip → S3 上传，前端每 2s 轮询状态。

后端:
- 新增 StartBackup/StartRestore 方法，后台 goroutine 不依赖 HTTP 连接
- Graceful shutdown 等待活跃操作完成，启动时清理孤立 running 记录
- BackupRecord 新增 progress/restore_status 字段支持进度和恢复状态追踪

前端:
- 创建备份/恢复后轮询 GET /backups/:id 直到完成或失败
- 标签页切换暂停/恢复轮询，组件卸载清理定时器
- 正确处理 409（备份进行中）和轮询超时

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/internal/handler/admin/backup_handler.go

@@ -98,12 +98,12 @@ func (h *BackupHandler) CreateBackup(c *gin.Context) {
 		expireDays = *req.ExpireDays
 	}
 
-	record, err := h.backupService.CreateBackup(c.Request.Context(), "manual", expireDays)
+	record, err := h.backupService.StartBackup(c.Request.Context(), "manual", expireDays)
 	if err != nil {
 		response.ErrorFrom(c, err)
 		return
 	}
-	response.Success(c, record)
+	response.Accepted(c, record)
 }
 
 func (h *BackupHandler) ListBackups(c *gin.Context) {
@@ -196,9 +196,10 @@ func (h *BackupHandler) RestoreBackup(c *gin.Context) {
 		return
 	}
 
-	if err := h.backupService.RestoreBackup(c.Request.Context(), backupID); err != nil {
+	record, err := h.backupService.StartRestore(c.Request.Context(), backupID)
+	if err != nil {
 		response.ErrorFrom(c, err)
 		return
 	}
-	response.Success(c, gin.H{"restored": true})
+	response.Accepted(c, record)
 }

backend/internal/pkg/response/response.go

@@ -47,6 +47,15 @@ func Created(c *gin.Context, data any) {
 	})
 }
 
+// Accepted 返回异步接受响应 (HTTP 202)
+func Accepted(c *gin.Context, data any) {
+	c.JSON(http.StatusAccepted, Response{
+		Code:    0,
+		Message: "accepted",
+		Data:    data,
+	})
+}
+
 // Error 返回错误响应
 func Error(c *gin.Context, statusCode int, message string) {
 	c.JSON(statusCode, Response{

backend/internal/repository/backup_s3_store.go

@@ -57,6 +57,7 @@ func NewS3BackupStoreFactory() service.BackupObjectStoreFactory {
 
 func (s *S3BackupStore) Upload(ctx context.Context, key string, body io.Reader, contentType string) (int64, error) {
 	// 读取全部内容以获取大小（S3 PutObject 需要知道内容长度）
+	// 注意：阿里云 OSS 不兼容 s3manager 分片上传的签名方式，因此使用 PutObject
 	data, err := io.ReadAll(body)
 	if err != nil {
 		return 0, fmt.Errorf("read body: %w", err)

backend/internal/service/backup_service.go

@@ -4,11 +4,13 @@ import (
 	"compress/gzip"
 	"context"
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io"
 	"sort"
 	"strings"
 	"sync"
+	"sync/atomic"
 	"time"
 
 	"github.com/google/uuid"
@@ -84,17 +86,21 @@ type BackupScheduleConfig struct {
 
 // BackupRecord 备份记录
 type BackupRecord struct {
-	ID          string `json:"id"`
-	Status      string `json:"status"`      // pending, running, completed, failed
-	BackupType  string `json:"backup_type"` // postgres
-	FileName    string `json:"file_name"`
-	S3Key       string `json:"s3_key"`
-	SizeBytes   int64  `json:"size_bytes"`
-	TriggeredBy string `json:"triggered_by"` // manual, scheduled
-	ErrorMsg    string `json:"error_message,omitempty"`
-	StartedAt   string `json:"started_at"`
-	FinishedAt  string `json:"finished_at,omitempty"`
-	ExpiresAt   string `json:"expires_at,omitempty"` // 过期时间
+	ID            string `json:"id"`
+	Status        string `json:"status"`      // pending, running, completed, failed
+	BackupType    string `json:"backup_type"` // postgres
+	FileName      string `json:"file_name"`
+	S3Key         string `json:"s3_key"`
+	SizeBytes     int64  `json:"size_bytes"`
+	TriggeredBy   string `json:"triggered_by"` // manual, scheduled
+	ErrorMsg      string `json:"error_message,omitempty"`
+	StartedAt     string `json:"started_at"`
+	FinishedAt    string `json:"finished_at,omitempty"`
+	ExpiresAt     string `json:"expires_at,omitempty"`     // 过期时间
+	Progress      string `json:"progress,omitempty"`       // "dumping", "uploading", ""
+	RestoreStatus string `json:"restore_status,omitempty"` // "", "running", "completed", "failed"
+	RestoreError  string `json:"restore_error,omitempty"`
+	RestoredAt    string `json:"restored_at,omitempty"`
 }
 
 // BackupService 数据库备份恢复服务
@@ -105,17 +111,24 @@ type BackupService struct {
 	storeFactory BackupObjectStoreFactory
 	dumper       DBDumper
 
-	mu        sync.Mutex
-	store     BackupObjectStore
-	s3Cfg     *BackupS3Config
+	opMu      sync.Mutex // 保护 backingUp/restoring 标志
 	backingUp bool
 	restoring bool
 
+	storeMu sync.Mutex // 保护 store/s3Cfg 缓存
+	store   BackupObjectStore
+	s3Cfg   *BackupS3Config
+
 	recordsMu sync.Mutex // 保护 records 的 load/save 操作
 
 	cronMu      sync.Mutex
 	cronSched   *cron.Cron
 	cronEntryID cron.EntryID
+
+	wg           sync.WaitGroup     // 追踪活跃的备份/恢复 goroutine
+	shuttingDown atomic.Bool        // 阻止新备份启动
+	bgCtx        context.Context    // 所有后台操作的 parent context
+	bgCancel     context.CancelFunc // 取消所有活跃后台操作
 }
 
 func NewBackupService(
@@ -125,20 +138,26 @@ func NewBackupService(
 	storeFactory BackupObjectStoreFactory,
 	dumper DBDumper,
 ) *BackupService {
+	bgCtx, bgCancel := context.WithCancel(context.Background())
 	return &BackupService{
 		settingRepo:  settingRepo,
 		dbCfg:        &cfg.Database,
 		encryptor:    encryptor,
 		storeFactory: storeFactory,
 		dumper:       dumper,
+		bgCtx:        bgCtx,
+		bgCancel:     bgCancel,
 	}
 }
 
-// Start 启动定时备份调度器
+// Start 启动定时备份调度器并清理孤立记录
 func (s *BackupService) Start() {
 	s.cronSched = cron.New()
 	s.cronSched.Start()
 
+	// 清理重启后孤立的 running 记录
+	s.recoverStaleRecords()
+
 	// 加载已有的定时配置
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
@@ -154,13 +173,65 @@ func (s *BackupService) Start() {
 	}
 }
 
-// Stop 停止定时备份
+// recoverStaleRecords 启动时将孤立的 running 记录标记为 failed
+func (s *BackupService) recoverStaleRecords() {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	records, err := s.loadRecords(ctx)
+	if err != nil {
+		return
+	}
+	for i := range records {
+		if records[i].Status == "running" {
+			records[i].Status = "failed"
+			records[i].ErrorMsg = "interrupted by server restart"
+			records[i].Progress = ""
+			records[i].FinishedAt = time.Now().Format(time.RFC3339)
+			_ = s.saveRecord(ctx, &records[i])
+			logger.LegacyPrintf("service.backup", "[Backup] recovered stale running record: %s", records[i].ID)
+		}
+		if records[i].RestoreStatus == "running" {
+			records[i].RestoreStatus = "failed"
+			records[i].RestoreError = "interrupted by server restart"
+			_ = s.saveRecord(ctx, &records[i])
+			logger.LegacyPrintf("service.backup", "[Backup] recovered stale restoring record: %s", records[i].ID)
+		}
+	}
+}
+
+// Stop 停止定时备份并等待活跃操作完成
 func (s *BackupService) Stop() {
+	s.shuttingDown.Store(true)
+
 	s.cronMu.Lock()
-	defer s.cronMu.Unlock()
 	if s.cronSched != nil {
 		s.cronSched.Stop()
 	}
+	s.cronMu.Unlock()
+
+	// 等待活跃备份/恢复完成（最多 5 分钟）
+	done := make(chan struct{})
+	go func() {
+		s.wg.Wait()
+		close(done)
+	}()
+	select {
+	case <-done:
+		logger.LegacyPrintf("service.backup", "[Backup] all active operations finished")
+	case <-time.After(5 * time.Minute):
+		logger.LegacyPrintf("service.backup", "[Backup] shutdown timeout after 5min, cancelling active operations")
+		if s.bgCancel != nil {
+			s.bgCancel() // 取消所有后台操作
+		}
+		// 给 goroutine 时间响应取消并完成清理
+		select {
+		case <-done:
+			logger.LegacyPrintf("service.backup", "[Backup] active operations cancelled and cleaned up")
+		case <-time.After(10 * time.Second):
+			logger.LegacyPrintf("service.backup", "[Backup] goroutine cleanup timed out")
+		}
+	}
 }
 
 // ─── S3 配置管理 ───
@@ -203,10 +274,10 @@ func (s *BackupService) UpdateS3Config(ctx context.Context, cfg BackupS3Config)
 	}
 
 	// 清除缓存的 S3 客户端
-	s.mu.Lock()
+	s.storeMu.Lock()
 	s.store = nil
 	s.s3Cfg = nil
-	s.mu.Unlock()
+	s.storeMu.Unlock()
 
 	cfg.SecretAccessKey = ""
 	return &cfg, nil
@@ -314,7 +385,10 @@ func (s *BackupService) removeCronSchedule() {
 }
 
 func (s *BackupService) runScheduledBackup() {
-	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Minute)
+	s.wg.Add(1)
+	defer s.wg.Done()
+
+	ctx, cancel := context.WithTimeout(s.bgCtx, 30*time.Minute)
 	defer cancel()
 
 	// 读取定时备份配置中的过期天数
@@ -327,7 +401,11 @@ func (s *BackupService) runScheduledBackup() {
 	logger.LegacyPrintf("service.backup", "[Backup] 开始执行定时备份, 过期天数: %d", expireDays)
 	record, err := s.CreateBackup(ctx, "scheduled", expireDays)
 	if err != nil {
-		logger.LegacyPrintf("service.backup", "[Backup] 定时备份失败: %v", err)
+		if errors.Is(err, ErrBackupInProgress) {
+			logger.LegacyPrintf("service.backup", "[Backup] 定时备份跳过: 已有备份正在进行中")
+		} else {
+			logger.LegacyPrintf("service.backup", "[Backup] 定时备份失败: %v", err)
+		}
 		return
 	}
 	logger.LegacyPrintf("service.backup", "[Backup] 定时备份完成: id=%s size=%d", record.ID, record.SizeBytes)
@@ -346,17 +424,21 @@ func (s *BackupService) runScheduledBackup() {
 // CreateBackup 创建全量数据库备份并上传到 S3（流式处理）
 // expireDays: 备份过期天数，0=永不过期，默认14天
 func (s *BackupService) CreateBackup(ctx context.Context, triggeredBy string, expireDays int) (*BackupRecord, error) {
-	s.mu.Lock()
+	if s.shuttingDown.Load() {
+		return nil, infraerrors.ServiceUnavailable("SERVER_SHUTTING_DOWN", "server is shutting down")
+	}
+
+	s.opMu.Lock()
 	if s.backingUp {
-		s.mu.Unlock()
+		s.opMu.Unlock()
 		return nil, ErrBackupInProgress
 	}
 	s.backingUp = true
-	s.mu.Unlock()
+	s.opMu.Unlock()
 	defer func() {
-		s.mu.Lock()
+		s.opMu.Lock()
 		s.backingUp = false
-		s.mu.Unlock()
+		s.opMu.Unlock()
 	}()
 
 	s3Cfg, err := s.loadS3Config(ctx)
@@ -405,36 +487,47 @@ func (s *BackupService) CreateBackup(ctx context.Context, triggeredBy string, ex
 
 	// 使用 io.Pipe 将 gzip 压缩数据流式传递给 S3 上传
 	pr, pw := io.Pipe()
-	var gzipErr error
+	gzipDone := make(chan error, 1)
 	go func() {
+		defer func() {
+			if r := recover(); r != nil {
+				pw.CloseWithError(fmt.Errorf("gzip goroutine panic: %v", r)) //nolint:errcheck
+				gzipDone <- fmt.Errorf("gzip goroutine panic: %v", r)
+			}
+		}()
 		gzWriter := gzip.NewWriter(pw)
-		_, gzipErr = io.Copy(gzWriter, dumpReader)
-		if closeErr := gzWriter.Close(); closeErr != nil && gzipErr == nil {
-			gzipErr = closeErr
+		var gzErr error
+		_, gzErr = io.Copy(gzWriter, dumpReader)
+		if closeErr := gzWriter.Close(); closeErr != nil && gzErr == nil {
+			gzErr = closeErr
 		}
-		if closeErr := dumpReader.Close(); closeErr != nil && gzipErr == nil {
-			gzipErr = closeErr
+		if closeErr := dumpReader.Close(); closeErr != nil && gzErr == nil {
+			gzErr = closeErr
 		}
-		if gzipErr != nil {
-			_ = pw.CloseWithError(gzipErr)
+		if gzErr != nil {
+			_ = pw.CloseWithError(gzErr)
 		} else {
 			_ = pw.Close()
 		}
+		gzipDone <- gzErr
 	}()
 
 	contentType := "application/gzip"
 	sizeBytes, err := objectStore.Upload(ctx, s3Key, pr, contentType)
 	if err != nil {
+		_ = pr.CloseWithError(err) // 确保 gzip goroutine 不会悬挂
+		gzErr := <-gzipDone        // 安全等待 gzip goroutine 完成
 		record.Status = "failed"
 		errMsg := fmt.Sprintf("S3 upload failed: %v", err)
-		if gzipErr != nil {
-			errMsg = fmt.Sprintf("gzip/dump failed: %v", gzipErr)
+		if gzErr != nil {
+			errMsg = fmt.Sprintf("gzip/dump failed: %v", gzErr)
 		}
 		record.ErrorMsg = errMsg
 		record.FinishedAt = time.Now().Format(time.RFC3339)
 		_ = s.saveRecord(ctx, record)
 		return record, fmt.Errorf("backup upload: %w", err)
 	}
+	<-gzipDone // 确保 gzip goroutine 已退出
 
 	record.SizeBytes = sizeBytes
 	record.Status = "completed"
@@ -446,19 +539,187 @@ func (s *BackupService) CreateBackup(ctx context.Context, triggeredBy string, ex
 	return record, nil
 }
 
+// StartBackup 异步创建备份，立即返回 running 状态的记录
+func (s *BackupService) StartBackup(ctx context.Context, triggeredBy string, expireDays int) (*BackupRecord, error) {
+	if s.shuttingDown.Load() {
+		return nil, infraerrors.ServiceUnavailable("SERVER_SHUTTING_DOWN", "server is shutting down")
+	}
+
+	s.opMu.Lock()
+	if s.backingUp {
+		s.opMu.Unlock()
+		return nil, ErrBackupInProgress
+	}
+	s.backingUp = true
+	s.opMu.Unlock()
+
+	// 初始化阶段出错时自动重置标志
+	launched := false
+	defer func() {
+		if !launched {
+			s.opMu.Lock()
+			s.backingUp = false
+			s.opMu.Unlock()
+		}
+	}()
+
+	// 在返回前加载 S3 配置和创建 store，避免 goroutine 中配置被修改
+	s3Cfg, err := s.loadS3Config(ctx)
+	if err != nil {
+		return nil, err
+	}
+	if s3Cfg == nil || !s3Cfg.IsConfigured() {
+		return nil, ErrBackupS3NotConfigured
+	}
+
+	objectStore, err := s.getOrCreateStore(ctx, s3Cfg)
+	if err != nil {
+		return nil, fmt.Errorf("init object store: %w", err)
+	}
+
+	now := time.Now()
+	backupID := uuid.New().String()[:8]
+	fileName := fmt.Sprintf("%s_%s.sql.gz", s.dbCfg.DBName, now.Format("20060102_150405"))
+	s3Key := s.buildS3Key(s3Cfg, fileName)
+
+	var expiresAt string
+	if expireDays > 0 {
+		expiresAt = now.AddDate(0, 0, expireDays).Format(time.RFC3339)
+	}
+
+	record := &BackupRecord{
+		ID:          backupID,
+		Status:      "running",
+		BackupType:  "postgres",
+		FileName:    fileName,
+		S3Key:       s3Key,
+		TriggeredBy: triggeredBy,
+		StartedAt:   now.Format(time.RFC3339),
+		ExpiresAt:   expiresAt,
+		Progress:    "pending",
+	}
+
+	if err := s.saveRecord(ctx, record); err != nil {
+		return nil, fmt.Errorf("save initial record: %w", err)
+	}
+
+	launched = true
+	// 在启动 goroutine 前完成拷贝，避免数据竞争
+	result := *record
+
+	s.wg.Add(1)
+	go func() {
+		defer s.wg.Done()
+		defer func() {
+			s.opMu.Lock()
+			s.backingUp = false
+			s.opMu.Unlock()
+		}()
+		defer func() {
+			if r := recover(); r != nil {
+				logger.LegacyPrintf("service.backup", "[Backup] panic recovered: %v", r)
+				record.Status = "failed"
+				record.ErrorMsg = fmt.Sprintf("internal panic: %v", r)
+				record.Progress = ""
+				record.FinishedAt = time.Now().Format(time.RFC3339)
+				_ = s.saveRecord(context.Background(), record)
+			}
+		}()
+		s.executeBackup(record, objectStore)
+	}()
+
+	return &result, nil
+}
+
+// executeBackup 后台执行备份（独立于 HTTP context）
+func (s *BackupService) executeBackup(record *BackupRecord, objectStore BackupObjectStore) {
+	ctx, cancel := context.WithTimeout(s.bgCtx, 30*time.Minute)
+	defer cancel()
+
+	// 阶段1: pg_dump
+	record.Progress = "dumping"
+	_ = s.saveRecord(ctx, record)
+
+	dumpReader, err := s.dumper.Dump(ctx)
+	if err != nil {
+		record.Status = "failed"
+		record.ErrorMsg = fmt.Sprintf("pg_dump failed: %v", err)
+		record.Progress = ""
+		record.FinishedAt = time.Now().Format(time.RFC3339)
+		_ = s.saveRecord(context.Background(), record)
+		return
+	}
+
+	// 阶段2: gzip + upload
+	record.Progress = "uploading"
+	_ = s.saveRecord(ctx, record)
+
+	pr, pw := io.Pipe()
+	gzipDone := make(chan error, 1)
+	go func() {
+		defer func() {
+			if r := recover(); r != nil {
+				pw.CloseWithError(fmt.Errorf("gzip goroutine panic: %v", r)) //nolint:errcheck
+				gzipDone <- fmt.Errorf("gzip goroutine panic: %v", r)
+			}
+		}()
+		gzWriter := gzip.NewWriter(pw)
+		var gzErr error
+		_, gzErr = io.Copy(gzWriter, dumpReader)
+		if closeErr := gzWriter.Close(); closeErr != nil && gzErr == nil {
+			gzErr = closeErr
+		}
+		if closeErr := dumpReader.Close(); closeErr != nil && gzErr == nil {
+			gzErr = closeErr
+		}
+		if gzErr != nil {
+			_ = pw.CloseWithError(gzErr)
+		} else {
+			_ = pw.Close()
+		}
+		gzipDone <- gzErr
+	}()
+
+	contentType := "application/gzip"
+	sizeBytes, err := objectStore.Upload(ctx, record.S3Key, pr, contentType)
+	if err != nil {
+		_ = pr.CloseWithError(err) // 确保 gzip goroutine 不会悬挂
+		gzErr := <-gzipDone        // 安全等待 gzip goroutine 完成
+		record.Status = "failed"
+		errMsg := fmt.Sprintf("S3 upload failed: %v", err)
+		if gzErr != nil {
+			errMsg = fmt.Sprintf("gzip/dump failed: %v", gzErr)
+		}
+		record.ErrorMsg = errMsg
+		record.Progress = ""
+		record.FinishedAt = time.Now().Format(time.RFC3339)
+		_ = s.saveRecord(context.Background(), record)
+		return
+	}
+	<-gzipDone // 确保 gzip goroutine 已退出
+
+	record.SizeBytes = sizeBytes
+	record.Status = "completed"
+	record.Progress = ""
+	record.FinishedAt = time.Now().Format(time.RFC3339)
+	if err := s.saveRecord(context.Background(), record); err != nil {
+		logger.LegacyPrintf("service.backup", "[Backup] 保存备份记录失败: %v", err)
+	}
+}
+
 // RestoreBackup 从 S3 下载备份并流式恢复到数据库
 func (s *BackupService) RestoreBackup(ctx context.Context, backupID string) error {
-	s.mu.Lock()
+	s.opMu.Lock()
 	if s.restoring {
-		s.mu.Unlock()
+		s.opMu.Unlock()
 		return ErrRestoreInProgress
 	}
 	s.restoring = true
-	s.mu.Unlock()
+	s.opMu.Unlock()
 	defer func() {
-		s.mu.Lock()
+		s.opMu.Lock()
 		s.restoring = false
-		s.mu.Unlock()
+		s.opMu.Unlock()
 	}()
 
 	record, err := s.GetBackupRecord(ctx, backupID)
@@ -500,6 +761,112 @@ func (s *BackupService) RestoreBackup(ctx context.Context, backupID string) erro
 	return nil
 }
 
+// StartRestore 异步恢复备份，立即返回
+func (s *BackupService) StartRestore(ctx context.Context, backupID string) (*BackupRecord, error) {
+	if s.shuttingDown.Load() {
+		return nil, infraerrors.ServiceUnavailable("SERVER_SHUTTING_DOWN", "server is shutting down")
+	}
+
+	s.opMu.Lock()
+	if s.restoring {
+		s.opMu.Unlock()
+		return nil, ErrRestoreInProgress
+	}
+	s.restoring = true
+	s.opMu.Unlock()
+
+	// 初始化阶段出错时自动重置标志
+	launched := false
+	defer func() {
+		if !launched {
+			s.opMu.Lock()
+			s.restoring = false
+			s.opMu.Unlock()
+		}
+	}()
+
+	record, err := s.GetBackupRecord(ctx, backupID)
+	if err != nil {
+		return nil, err
+	}
+	if record.Status != "completed" {
+		return nil, infraerrors.BadRequest("BACKUP_NOT_COMPLETED", "can only restore from a completed backup")
+	}
+
+	s3Cfg, err := s.loadS3Config(ctx)
+	if err != nil {
+		return nil, err
+	}
+	objectStore, err := s.getOrCreateStore(ctx, s3Cfg)
+	if err != nil {
+		return nil, fmt.Errorf("init object store: %w", err)
+	}
+
+	record.RestoreStatus = "running"
+	_ = s.saveRecord(ctx, record)
+
+	launched = true
+	result := *record
+
+	s.wg.Add(1)
+	go func() {
+		defer s.wg.Done()
+		defer func() {
+			s.opMu.Lock()
+			s.restoring = false
+			s.opMu.Unlock()
+		}()
+		defer func() {
+			if r := recover(); r != nil {
+				logger.LegacyPrintf("service.backup", "[Backup] restore panic recovered: %v", r)
+				record.RestoreStatus = "failed"
+				record.RestoreError = fmt.Sprintf("internal panic: %v", r)
+				_ = s.saveRecord(context.Background(), record)
+			}
+		}()
+		s.executeRestore(record, objectStore)
+	}()
+
+	return &result, nil
+}
+
+// executeRestore 后台执行恢复
+func (s *BackupService) executeRestore(record *BackupRecord, objectStore BackupObjectStore) {
+	ctx, cancel := context.WithTimeout(s.bgCtx, 30*time.Minute)
+	defer cancel()
+
+	body, err := objectStore.Download(ctx, record.S3Key)
+	if err != nil {
+		record.RestoreStatus = "failed"
+		record.RestoreError = fmt.Sprintf("S3 download failed: %v", err)
+		_ = s.saveRecord(context.Background(), record)
+		return
+	}
+	defer func() { _ = body.Close() }()
+
+	gzReader, err := gzip.NewReader(body)
+	if err != nil {
+		record.RestoreStatus = "failed"
+		record.RestoreError = fmt.Sprintf("gzip reader: %v", err)
+		_ = s.saveRecord(context.Background(), record)
+		return
+	}
+	defer func() { _ = gzReader.Close() }()
+
+	if err := s.dumper.Restore(ctx, gzReader); err != nil {
+		record.RestoreStatus = "failed"
+		record.RestoreError = fmt.Sprintf("pg restore: %v", err)
+		_ = s.saveRecord(context.Background(), record)
+		return
+	}
+
+	record.RestoreStatus = "completed"
+	record.RestoredAt = time.Now().Format(time.RFC3339)
+	if err := s.saveRecord(context.Background(), record); err != nil {
+		logger.LegacyPrintf("service.backup", "[Backup] 保存恢复记录失败: %v", err)
+	}
+}
+
 // ─── 备份记录管理 ───
 
 func (s *BackupService) ListBackups(ctx context.Context) ([]BackupRecord, error) {
@@ -614,8 +981,8 @@ func (s *BackupService) loadS3Config(ctx context.Context) (*BackupS3Config, erro
 }
 
 func (s *BackupService) getOrCreateStore(ctx context.Context, cfg *BackupS3Config) (BackupObjectStore, error) {
-	s.mu.Lock()
-	defer s.mu.Unlock()
+	s.storeMu.Lock()
+	defer s.storeMu.Unlock()
 
 	if s.store != nil && s.s3Cfg != nil {
 		return s.store, nil

backend/internal/service/backup_service_test.go

@@ -134,6 +134,30 @@ func (m *mockDumper) Restore(_ context.Context, data io.Reader) error {
 	return nil
 }
 
+// blockingDumper 可控延迟的 dumper，用于测试异步行为
+type blockingDumper struct {
+	blockCh chan struct{}
+	data    []byte
+	restErr error
+}
+
+func (d *blockingDumper) Dump(ctx context.Context) (io.ReadCloser, error) {
+	select {
+	case <-d.blockCh:
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+	return io.NopCloser(bytes.NewReader(d.data)), nil
+}
+
+func (d *blockingDumper) Restore(_ context.Context, data io.Reader) error {
+	if d.restErr != nil {
+		return d.restErr
+	}
+	_, _ = io.ReadAll(data)
+	return nil
+}
+
 type mockObjectStore struct {
 	objects map[string][]byte
 	mu      sync.Mutex
@@ -179,7 +203,7 @@ func (m *mockObjectStore) HeadBucket(_ context.Context) error {
 	return nil
 }
 
-func newTestBackupService(repo *mockSettingRepo, dumper *mockDumper, store *mockObjectStore) *BackupService {
+func newTestBackupService(repo *mockSettingRepo, dumper DBDumper, store *mockObjectStore) *BackupService {
 	cfg := &config.Config{
 		Database: config.DatabaseConfig{
 			Host:   "localhost",
@@ -361,9 +385,9 @@ func TestBackupService_CreateBackup_ConcurrentBlocked(t *testing.T) {
 	svc := newTestBackupService(repo, dumper, store)
 
 	// 手动设置 backingUp 标志
-	svc.mu.Lock()
+	svc.opMu.Lock()
 	svc.backingUp = true
-	svc.mu.Unlock()
+	svc.opMu.Unlock()
 
 	_, err := svc.CreateBackup(context.Background(), "manual", 14)
 	require.ErrorIs(t, err, ErrBackupInProgress)
@@ -526,3 +550,154 @@ func TestBackupService_LoadS3Config_Corrupted(t *testing.T) {
 	require.Error(t, err)
 	require.Nil(t, cfg)
 }
+
+// ─── Async Backup Tests ───
+
+func TestStartBackup_ReturnsImmediately(t *testing.T) {
+	repo := newMockSettingRepo()
+	seedS3Config(t, repo)
+
+	dumper := &blockingDumper{blockCh: make(chan struct{}), data: []byte("data")}
+	store := newMockObjectStore()
+	svc := newTestBackupService(repo, dumper, store)
+
+	record, err := svc.StartBackup(context.Background(), "manual", 14)
+	require.NoError(t, err)
+	require.Equal(t, "running", record.Status)
+	require.NotEmpty(t, record.ID)
+
+	// 释放 dumper 让后台完成
+	close(dumper.blockCh)
+	svc.wg.Wait()
+
+	// 验证最终状态
+	final, err := svc.GetBackupRecord(context.Background(), record.ID)
+	require.NoError(t, err)
+	require.Equal(t, "completed", final.Status)
+	require.Greater(t, final.SizeBytes, int64(0))
+}
+
+func TestStartBackup_ConcurrentBlocked(t *testing.T) {
+	repo := newMockSettingRepo()
+	seedS3Config(t, repo)
+
+	dumper := &blockingDumper{blockCh: make(chan struct{}), data: []byte("data")}
+	store := newMockObjectStore()
+	svc := newTestBackupService(repo, dumper, store)
+
+	// 第一次启动
+	_, err := svc.StartBackup(context.Background(), "manual", 14)
+	require.NoError(t, err)
+
+	// 第二次应被阻塞
+	_, err = svc.StartBackup(context.Background(), "manual", 14)
+	require.ErrorIs(t, err, ErrBackupInProgress)
+
+	close(dumper.blockCh)
+	svc.wg.Wait()
+}
+
+func TestStartBackup_ShuttingDown(t *testing.T) {
+	repo := newMockSettingRepo()
+	seedS3Config(t, repo)
+	svc := newTestBackupService(repo, &mockDumper{dumpData: []byte("data")}, newMockObjectStore())
+
+	svc.shuttingDown.Store(true)
+
+	_, err := svc.StartBackup(context.Background(), "manual", 14)
+	require.Error(t, err)
+	require.Contains(t, err.Error(), "shutting down")
+}
+
+func TestRecoverStaleRecords(t *testing.T) {
+	repo := newMockSettingRepo()
+	svc := newTestBackupService(repo, &mockDumper{}, newMockObjectStore())
+
+	// 模拟一条孤立的 running 记录
+	_ = svc.saveRecord(context.Background(), &BackupRecord{
+		ID:        "stale-1",
+		Status:    "running",
+		StartedAt: time.Now().Add(-1 * time.Hour).Format(time.RFC3339),
+	})
+	// 模拟一条孤立的恢复中记录
+	_ = svc.saveRecord(context.Background(), &BackupRecord{
+		ID:            "stale-2",
+		Status:        "completed",
+		RestoreStatus: "running",
+		StartedAt:     time.Now().Add(-1 * time.Hour).Format(time.RFC3339),
+	})
+
+	svc.recoverStaleRecords()
+
+	r1, _ := svc.GetBackupRecord(context.Background(), "stale-1")
+	require.Equal(t, "failed", r1.Status)
+	require.Contains(t, r1.ErrorMsg, "server restart")
+
+	r2, _ := svc.GetBackupRecord(context.Background(), "stale-2")
+	require.Equal(t, "failed", r2.RestoreStatus)
+	require.Contains(t, r2.RestoreError, "server restart")
+}
+
+func TestGracefulShutdown(t *testing.T) {
+	repo := newMockSettingRepo()
+	seedS3Config(t, repo)
+
+	dumper := &blockingDumper{blockCh: make(chan struct{}), data: []byte("data")}
+	store := newMockObjectStore()
+	svc := newTestBackupService(repo, dumper, store)
+
+	_, err := svc.StartBackup(context.Background(), "manual", 14)
+	require.NoError(t, err)
+
+	// Stop 应该等待备份完成
+	done := make(chan struct{})
+	go func() {
+		svc.Stop()
+		close(done)
+	}()
+
+	// 短暂等待确认 Stop 还在等待
+	select {
+	case <-done:
+		t.Fatal("Stop returned before backup finished")
+	case <-time.After(100 * time.Millisecond):
+		// 预期：Stop 还在等待
+	}
+
+	// 释放备份
+	close(dumper.blockCh)
+
+	// 现在 Stop 应该完成
+	select {
+	case <-done:
+		// 预期
+	case <-time.After(5 * time.Second):
+		t.Fatal("Stop did not return after backup finished")
+	}
+}
+
+func TestStartRestore_Async(t *testing.T) {
+	repo := newMockSettingRepo()
+	seedS3Config(t, repo)
+
+	dumpContent := "-- PostgreSQL dump\nCREATE TABLE test (id int);\n"
+	dumper := &mockDumper{dumpData: []byte(dumpContent)}
+	store := newMockObjectStore()
+	svc := newTestBackupService(repo, dumper, store)
+
+	// 先创建一个备份（同步方式）
+	record, err := svc.CreateBackup(context.Background(), "manual", 14)
+	require.NoError(t, err)
+
+	// 异步恢复
+	restored, err := svc.StartRestore(context.Background(), record.ID)
+	require.NoError(t, err)
+	require.Equal(t, "running", restored.RestoreStatus)
+
+	svc.wg.Wait()
+
+	// 验证最终状态
+	final, err := svc.GetBackupRecord(context.Background(), record.ID)
+	require.NoError(t, err)
+	require.Equal(t, "completed", final.RestoreStatus)
+}