diff --git a/.nogitrelease b/.nogitrelease
new file mode 100644
index 000000000000..e69de29bb2d1
diff --git a/include/sys/fs/zfs.h b/include/sys/fs/zfs.h
index 8c949e7671a0..bfcc01497dbb 100644
--- a/include/sys/fs/zfs.h
+++ b/include/sys/fs/zfs.h
@@ -707,6 +707,7 @@ typedef struct vdev_stat {
 	uint64_t	vs_self_healed;		/* self-healed bytes	*/
 	uint64_t	vs_scan_removing;	/* removing?	*/
 	uint64_t	vs_scan_processed;	/* scan processed bytes	*/
+	uint64_t	vs_request_time_average;/* avg. request time <<8*/
 } vdev_stat_t;
 
 /*
diff --git a/include/sys/vdev.h b/include/sys/vdev.h
index f49086a4776c..49c8fcb6fb02 100644
--- a/include/sys/vdev.h
+++ b/include/sys/vdev.h
@@ -69,6 +69,7 @@ extern void vdev_dtl_reassess(vdev_t *vd, uint64_t txg, uint64_t scrub_txg,
 extern boolean_t vdev_dtl_required(vdev_t *vd);
 extern boolean_t vdev_resilver_needed(vdev_t *vd,
     uint64_t *minp, uint64_t *maxp);
+extern uint64_t vdev_pending_queued(vdev_t *vd);
 
 extern void vdev_hold(vdev_t *);
 extern void vdev_rele(vdev_t *);
diff --git a/module/zfs/vdev.c b/module/zfs/vdev.c
index c44e4f67f068..4698a3d02f1f 100644
--- a/module/zfs/vdev.c
+++ b/module/zfs/vdev.c
@@ -1948,6 +1948,23 @@ vdev_resilver_needed(vdev_t *vd, uint64_t *minp, uint64_t *maxp)
 	return (needed);
 }
 
+uint64_t
+vdev_pending_queued(vdev_t *vd)
+{
+	int pending;
+	uint64_t estimate;
+	vdev_queue_t *vq = &vd->vdev_queue;
+	vdev_stat_t *vs = &vd->vdev_stat;
+
+	mutex_enter(&vq->vq_lock);
+	pending = avl_numnodes(&vq->vq_pending_tree);
+	mutex_exit(&vq->vq_lock);
+	pending++;
+	estimate = vs->vs_request_time_average >> 8;
+	estimate = estimate * pending;
+	return (estimate);
+}
+
 void
 vdev_load(vdev_t *vd)
 {
@@ -2614,7 +2631,9 @@ vdev_stat_update(zio_t *zio, uint64_t psize)
 
 		vs->vs_ops[type]++;
 		vs->vs_bytes[type] += psize;
-
+		if (zio->io_timestamp > 0) {
+			vs->vs_request_time_average += ((uint64_t)(ddi_get_lbolt64() - zio->io_timestamp + 1) << 8) - (vs->vs_request_time_average >> 8);
+		}
 		mutex_exit(&vd->vdev_stat_lock);
 		return;
 	}
diff --git a/module/zfs/vdev_mirror.c b/module/zfs/vdev_mirror.c
index a2671ca81a37..3aec95042614 100644
--- a/module/zfs/vdev_mirror.c
+++ b/module/zfs/vdev_mirror.c
@@ -33,6 +33,8 @@
 #include <sys/zio.h>
 #include <sys/fs/zfs.h>
 
+int zfs_vdev_mirror_pending_balance = 0;
+
 /*
  * Virtual device vector for mirroring.
  */
@@ -221,7 +223,10 @@ vdev_mirror_child_select(zio_t *zio)
 	mirror_map_t *mm = zio->io_vsd;
 	mirror_child_t *mc;
 	uint64_t txg = zio->io_txg;
+	int pending_lowest_child = -1;
+	uint64_t pending_lowest_count = UINT64_MAX;
 	int i, c;
+	uint64_t pending;
 
 	ASSERT(zio->io_bp == NULL || BP_PHYSICAL_BIRTH(zio->io_bp) == txg);
 
@@ -243,12 +248,35 @@ vdev_mirror_child_select(zio_t *zio)
 			continue;
 		}
 		if (!vdev_dtl_contains(mc->mc_vd, DTL_MISSING, txg, 1))
-			return (c);
+		{
+			if (!zfs_vdev_mirror_pending_balance)	/* balance disabled */
+				return (c);
+			pending = vdev_pending_queued(mc->mc_vd);
+			if (pending == 0) {
+				return (c);
+			}
+			if (pending < pending_lowest_count) {
+				pending_lowest_count = pending;
+				pending_lowest_child = c;
+			}
+			else if (pending == pending_lowest_count) {
+				if ( c == mm->mm_preferred)
+					pending_lowest_child = c;
+			}
+			continue;
+		}
 		mc->mc_error = ESTALE;
 		mc->mc_skipped = 1;
 		mc->mc_speculative = 1;
 	}
 
+	/*
+	 * See if we found multiple devices with pending io's
+	 * and return the child with smallest queue.
+	 */
+	if ( pending_lowest_child != -1 )
+		return (pending_lowest_child);
+
 	/*
 	 * Every device is either missing or has this txg in its DTL.
 	 * Look for any child we haven't already tried before giving up.
@@ -492,3 +520,8 @@ vdev_ops_t vdev_spare_ops = {
 	VDEV_TYPE_SPARE,	/* name of this vdev type */
 	B_FALSE			/* not a leaf vdev */
 };
+
+#if defined(_KERNEL) && defined(HAVE_SPL)
+module_param(zfs_vdev_mirror_pending_balance, int, 0644);
+MODULE_PARM_DESC(zfs_vdev_mirror_pending_balance, "Balance reads from mirror vdev based on member speed and pending queue depth");
+#endif