diff --git a/module/zfs/metaslab.c b/module/zfs/metaslab.c
index 35bd968f6..c1424a81b 100644
--- a/module/zfs/metaslab.c
+++ b/module/zfs/metaslab.c
@@ -3545,6 +3545,15 @@ metaslab_segment_may_passivate(metaslab_t *msp)
 	if (WEIGHT_IS_SPACEBASED(msp->ms_weight) || spa_sync_pass(spa) > 1)
 		return;
 
+	/*
+	 * As long as a single largest free segment covers majorioty of free
+	 * space, don't consider the metaslab fragmented.  It should allow
+	 * us to fill new unfragmented metaslabs full before switching.
+	 */
+	if (metaslab_largest_allocatable(msp) >
+	    zfs_range_tree_space(msp->ms_allocatable) * 15 / 16)
+		return;
+
 	/*
 	 * Since we are in the middle of a sync pass, the most accurate
 	 * information that is accessible to us is the in-core range tree