diff --git a/WHATS_NEW b/WHATS_NEW
index 2b22b3164..6a55c8b3f 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 2.02.93 - 
 ====================================
+  Fix allocation code to allow replacement of single RAID 4/5/6 device.
   Check all tags and LV names are in a valid form in vg_validate.
   Add tmpfiles.d style configuration for lvm2 lock and run directory.
   Add configure --with-tmpfilesdir for dir holding volatile-file configuration.
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index a8a52a49a..a743c075f 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -737,7 +737,7 @@ static struct alloc_handle *_alloc_init(struct cmd_context *cmd,
 					struct dm_list *parallel_areas)
 {
 	struct alloc_handle *ah;
-	uint32_t s, area_count, alloc_count;
+	uint32_t s, area_count, alloc_count, parity_count;
 	size_t size = 0;
 
 	/* FIXME Caller should ensure this */
@@ -752,7 +752,9 @@ static struct alloc_handle *_alloc_init(struct cmd_context *cmd,
 		area_count = stripes;
 
 	size = sizeof(*ah);
-	alloc_count = area_count + segtype->parity_devs;
+	parity_count = (area_count <= segtype->parity_devs) ? 0 :
+		segtype->parity_devs;
+	alloc_count = area_count + parity_count;
 	if (segtype_is_raid(segtype) && metadata_area_count)
 		/* RAID has a meta area for each device */
 		alloc_count *= 2;
@@ -787,7 +789,7 @@ static struct alloc_handle *_alloc_init(struct cmd_context *cmd,
 	else
 		ah->new_extents = 0;
 	ah->area_count = area_count;
-	ah->parity_count = segtype->parity_devs;
+	ah->parity_count = parity_count;
 	ah->region_size = region_size;
 	ah->alloc = alloc;
 	ah->area_multiple = _calc_area_multiple(segtype, area_count, stripes);
diff --git a/lib/metadata/raid_manip.c b/lib/metadata/raid_manip.c
index 50918a8cb..e60af1769 100644
--- a/lib/metadata/raid_manip.c
+++ b/lib/metadata/raid_manip.c
@@ -493,6 +493,7 @@ static int _alloc_image_components(struct logical_volume *lv,
 {
 	uint32_t s;
 	uint32_t region_size;
+	uint32_t extents;
 	struct lv_segment *seg = first_seg(lv);
 	const struct segment_type *segtype;
 	struct alloc_handle *ah;
@@ -518,8 +519,11 @@ static int _alloc_image_components(struct logical_volume *lv,
 	else if (!(segtype = get_segtype_from_string(lv->vg->cmd, "raid1")))
 		return_0;
 
+	extents = (segtype->parity_devs) ?
+		(lv->le_count / (seg->area_count - segtype->parity_devs)) :
+		lv->le_count;
 	if (!(ah = allocate_extents(lv->vg, NULL, segtype, 0, count, count,
-				    region_size, lv->le_count, pvs,
+				    region_size, extents, pvs,
 				    lv->alloc, parallel_areas)))
 		return_0;