diff --git a/jobs/job.go b/jobs/job.go
index e18fe8fc0722461f8f504d375eeefaa202ea063e..646727fb10a4bcf7d4f5102b69bd12a26a185a41 100644
--- a/jobs/job.go
+++ b/jobs/job.go
@@ -212,7 +212,9 @@ type QueueSpec struct {
 // NewQueueManager returns a new QueueManager with the provided
 // configuration.
 func NewQueueManager(spec *QueueSpec) *QueueManager {
-	q := make(map[string]chan struct{})
+	q := map[string]chan struct{}{
+		"default": make(chan struct{}, 2),
+	}
 	for name, n := range spec.Workers {
 		q[name] = make(chan struct{}, n)
 	}
diff --git a/manager.go b/manager.go
index 7d89dc24b38a733728d57d999e0331a1903f33de..d0db333066666a6674817cf4e9c966b27d8e1d05 100644
--- a/manager.go
+++ b/manager.go
@@ -125,14 +125,16 @@ func (m *tabaccoManager) makeBackupJob(ctx context.Context, rctx RuntimeContext,
 
 	// The actual backup operation. Assemble all the backup jobs
 	// for the datasets in 'dsl', and add them to an AsyncGroup.
-	//
-	// TODO: get the timeout from the SourceSpec.
+	// Limit concurrency in the AsyncGroup.
 	var backupJobs []jobs.Job
 	for _, ds := range dsl {
-		backupJobs = append(backupJobs, m.withMetadata(
-			h.BackupJob(rctx, backup, ds),
-			backup,
-			ds,
+		backupJobs = append(backupJobs, m.WithQueue(
+			m.withMetadata(
+				h.BackupJob(rctx, backup, ds),
+				backup,
+				ds,
+			),
+			"dataset",
 		))
 	}
 
@@ -166,7 +168,7 @@ func (m *tabaccoManager) makeBackupJob(ctx context.Context, rctx RuntimeContext,
 				false),
 			id,
 		),
-		"backup",
+		"source",
 	), nil
 }
 
@@ -209,7 +211,10 @@ func (m *tabaccoManager) makeRestoreJob(rctx RuntimeContext, backup *Backup, src
 	for _, ds := range dsl {
 		restoreJobs = append(
 			restoreJobs,
-			h.RestoreJob(rctx, backup, ds, target),
+			m.WithQueue(
+				h.RestoreJob(rctx, backup, ds, target),
+				"dataset",
+			),
 		)
 	}