diff --git a/weed/topology/node.go b/weed/topology/node.go
index 3e22e03fb..a8edb828a 100644
--- a/weed/topology/node.go
+++ b/weed/topology/node.go
@@ -61,11 +61,7 @@ func (cr *CapacityReservations) removeReservation(reservationId string) bool {
 
 	if reservation, exists := cr.reservations[reservationId]; exists {
 		delete(cr.reservations, reservationId)
-		cr.reservedCounts[reservation.diskType] -= reservation.count
-		// Clean up zero counts to prevent map growth
-		if cr.reservedCounts[reservation.diskType] <= 0 {
-			delete(cr.reservedCounts, reservation.diskType)
-		}
+		cr.decrementCount(reservation.diskType, reservation.count)
 		return true
 	}
 	return false
@@ -78,6 +74,40 @@ func (cr *CapacityReservations) getReservedCount(diskType types.DiskType) int64
 	return cr.reservedCounts[diskType]
 }
 
+// decrementCount is a helper to decrement reserved count and clean up zero entries
+func (cr *CapacityReservations) decrementCount(diskType types.DiskType, count int64) {
+	cr.reservedCounts[diskType] -= count
+	// Clean up zero counts to prevent map growth
+	if cr.reservedCounts[diskType] <= 0 {
+		delete(cr.reservedCounts, diskType)
+	}
+}
+
+// tryReserveAtomic atomically checks available space and reserves if possible
+func (cr *CapacityReservations) tryReserveAtomic(diskType types.DiskType, count int64, availableSpaceFunc func() int64) (reservationId string, success bool) {
+	cr.Lock()
+	defer cr.Unlock()
+
+	// Check available space under lock
+	currentReserved := cr.reservedCounts[diskType]
+	availableSpace := availableSpaceFunc() - currentReserved
+
+	if availableSpace >= count {
+		// Create and add reservation atomically
+		reservationId = fmt.Sprintf("%s-%d-%d-%d", diskType, count, time.Now().UnixNano(), rand.Int64())
+		cr.reservations[reservationId] = &CapacityReservation{
+			reservationId: reservationId,
+			diskType:      diskType,
+			count:         count,
+			createdAt:     time.Now(),
+		}
+		cr.reservedCounts[diskType] += count
+		return reservationId, true
+	}
+
+	return "", false
+}
+
 func (cr *CapacityReservations) cleanExpiredReservations(expirationDuration time.Duration) {
 	cr.Lock()
 	defer cr.Unlock()
@@ -86,11 +116,7 @@ func (cr *CapacityReservations) cleanExpiredReservations(expirationDuration time
 	for id, reservation := range cr.reservations {
 		if now.Sub(reservation.createdAt) > expirationDuration {
 			delete(cr.reservations, id)
-			cr.reservedCounts[reservation.diskType] -= reservation.count
-			// Clean up zero counts to prevent map growth
-			if cr.reservedCounts[reservation.diskType] <= 0 {
-				delete(cr.reservedCounts, reservation.diskType)
-			}
+			cr.decrementCount(reservation.diskType, reservation.count)
 			glog.V(1).Infof("Cleaned up expired capacity reservation: %s", id)
 		}
 	}
@@ -262,23 +288,22 @@ func (n *NodeImpl) AvailableSpaceForReservation(option *VolumeGrowOption) int64
 
 // TryReserveCapacity attempts to atomically reserve capacity for volume creation
 func (n *NodeImpl) TryReserveCapacity(diskType types.DiskType, count int64) (reservationId string, success bool) {
-	const reservationTimeout = 5 * time.Minute
+	const reservationTimeout = 5 * time.Minute // TODO: make this configurable
 
 	// Clean up any expired reservations first
 	n.capacityReservations.cleanExpiredReservations(reservationTimeout)
 
-	// Check for available space using the optimized method
+	// Atomically check and reserve space
 	option := &VolumeGrowOption{DiskType: diskType}
-	availableSpace := n.AvailableSpaceForReservation(option)
+	reservationId, success = n.capacityReservations.tryReserveAtomic(diskType, count, func() int64 {
+		return n.AvailableSpaceFor(option)
+	})
 
-	if availableSpace >= count {
-		// Add new reservation using the optimized method
-		reservationId = n.capacityReservations.addReservation(diskType, count)
+	if success {
 		glog.V(1).Infof("Reserved %d capacity for diskType %s on node %s: %s", count, diskType, n.Id(), reservationId)
-		return reservationId, true
 	}
 
-	return "", false
+	return reservationId, success
 }
 
 // ReleaseReservedCapacity releases a previously reserved capacity
diff --git a/weed/topology/volume_growth.go b/weed/topology/volume_growth.go
index 8344168a0..2500d08d2 100644
--- a/weed/topology/volume_growth.go
+++ b/weed/topology/volume_growth.go
@@ -183,6 +183,13 @@ func (vg *VolumeGrowth) findAndGrow(grpcDialOption grpc.DialOption, topo *Topolo
 func (vg *VolumeGrowth) findEmptySlotsForOneVolume(topo *Topology, option *VolumeGrowOption, useReservations bool) (servers []*DataNode, reservation *VolumeGrowReservation, err error) {
 	//find main datacenter and other data centers
 	rp := option.ReplicaPlacement
+
+	// Ensure cleanup of partial reservations on error
+	defer func() {
+		if err != nil && reservation != nil {
+			reservation.releaseAllReservations()
+		}
+	}()
 	mainDataCenter, otherDataCenters, dc_err := topo.PickNodesByWeight(rp.DiffDataCenterCount+1, option, func(node Node) error {
 		if option.DataCenter != "" && node.IsDataCenter() && node.Id() != NodeId(option.DataCenter) {
 			return fmt.Errorf("Not matching preferred data center:%s", option.DataCenter)