diff --git a/lib/metadata/lv_alloc.h b/lib/metadata/lv_alloc.h
index acfebcada..395420d6e 100644
--- a/lib/metadata/lv_alloc.h
+++ b/lib/metadata/lv_alloc.h
@@ -54,7 +54,7 @@ struct alloc_handle *allocate_extents(struct volume_group *vg,
                                       uint32_t mirrors, uint32_t log_count,
 				      uint32_t log_region_size, uint32_t extents,
                                       struct dm_list *allocatable_pvs,
-				      alloc_policy_t alloc,
+				      alloc_policy_t alloc, int approx_alloc,
 				      struct dm_list *parallel_areas);
 
 int lv_add_segment(struct alloc_handle *ah,
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 826dbb2e7..d38dd7cd5 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -918,6 +918,7 @@ struct alloc_handle {
 	struct dm_pool *mem;
 
 	alloc_policy_t alloc;		/* Overall policy */
+	int approx_alloc;                /* get as much as possible up to new_extents */
 	uint32_t new_extents;		/* Number of new extents required */
 	uint32_t area_count;		/* Number of parallel areas */
 	uint32_t parity_count;   /* Adds to area_count, but not area_multiple */
@@ -1041,7 +1042,7 @@ static uint32_t mirror_log_extents(uint32_t region_size, uint32_t pe_size, uint3
 static struct alloc_handle *_alloc_init(struct cmd_context *cmd,
 					struct dm_pool *mem,
 					const struct segment_type *segtype,
-					alloc_policy_t alloc,
+					alloc_policy_t alloc, int approx_alloc,
 					uint32_t new_extents,
 					uint32_t mirrors,
 					uint32_t stripes,
@@ -1194,6 +1195,7 @@ static struct alloc_handle *_alloc_init(struct cmd_context *cmd,
 
 	ah->maximise_cling = find_config_tree_bool(cmd, allocation_maximise_cling_CFG, NULL);
 
+	ah->approx_alloc = approx_alloc;
 	return ah;
 }
 
@@ -1214,10 +1216,18 @@ static int _sufficient_pes_free(struct alloc_handle *ah, struct dm_list *pvms,
 	uint32_t free_pes = pv_maps_size(pvms);
 
 	if (total_extents_needed > free_pes) {
-		log_error("Insufficient free space: %" PRIu32 " extents needed,"
-			  " but only %" PRIu32 " available",
-			  total_extents_needed, free_pes);
-		return 0;
+		if (!ah->approx_alloc) {
+			log_error("Insufficient free space: %" PRIu32
+				  " extents needed,"
+				  " but only %" PRIu32 " available",
+				  total_extents_needed, free_pes);
+
+			return 0;
+		}
+		log_verbose("Insufficient free space: %" PRIu32
+			    " extents needed, but only %" PRIu32
+			    " available: amount will be reduced",
+			    total_extents_needed, free_pes);
 	}
 
 	return 1;
@@ -2006,7 +2016,8 @@ static void _report_needed_allocation_space(struct alloc_handle *ah,
 		metadata_count = alloc_state->log_area_count_still_needed;
 	}
 
-	log_debug_alloc("Still need %" PRIu32 " total extents:",
+	log_debug_alloc("Still need %s%" PRIu32 " total extents:",
+			ah->approx_alloc ? "up to " : "",
 			parallel_area_size * parallel_areas_count + metadata_size * metadata_count);
 	log_debug_alloc("  %" PRIu32 " (%" PRIu32 " data/%" PRIu32
 			" parity) parallel areas of %" PRIu32 " extents each",
@@ -2414,19 +2425,29 @@ static int _allocate(struct alloc_handle *ah,
 		if (!_find_max_parallel_space_for_one_policy(ah, &alloc_parms, pvms, &alloc_state))
 			goto_out;
 
-		if ((alloc_state.allocated == ah->new_extents && !alloc_state.log_area_count_still_needed) ||
+		if ((alloc_state.allocated == ah->new_extents &&
+		     !alloc_state.log_area_count_still_needed) ||
 		    (!can_split && (alloc_state.allocated != old_allocated)))
 			break;
 	}
 
 	if (alloc_state.allocated != ah->new_extents) {
-		log_error("Insufficient suitable %sallocatable extents "
-			  "for logical volume %s: %u more required",
-			  can_split ? "" : "contiguous ",
-			  lv ? lv->name : "",
-			  (ah->new_extents - alloc_state.allocated) * ah->area_count
-			  / ah->area_multiple);
-		goto out;
+		if (!ah->approx_alloc) {
+			log_error("Insufficient suitable %sallocatable extents "
+				  "for logical volume %s: %u more required",
+				  can_split ? "" : "contiguous ",
+				  lv ? lv->name : "",
+				  (ah->new_extents - alloc_state.allocated) *
+				  ah->area_count / ah->area_multiple);
+			goto out;
+		}
+		log_verbose("Insufficient suitable %sallocatable extents "
+			    "for logical volume %s: size reduced by %u extents",
+			    can_split ? "" : "contiguous ",
+			    lv ? lv->name : "",
+			    (ah->new_extents - alloc_state.allocated) *
+			    ah->area_count / ah->area_multiple);
+		ah->new_extents = alloc_state.allocated;
 	}
 
 	if (alloc_state.log_area_count_still_needed) {
@@ -2503,7 +2524,7 @@ struct alloc_handle *allocate_extents(struct volume_group *vg,
 				      uint32_t mirrors, uint32_t log_count,
 				      uint32_t region_size, uint32_t extents,
 				      struct dm_list *allocatable_pvs,
-				      alloc_policy_t alloc,
+				      alloc_policy_t alloc, int approx_alloc,
 				      struct dm_list *parallel_areas)
 {
 	struct alloc_handle *ah;
@@ -2533,7 +2554,7 @@ struct alloc_handle *allocate_extents(struct volume_group *vg,
 		alloc = vg->alloc;
 
 	new_extents = (lv ? lv->le_count : 0) + extents;
-	if (!(ah = _alloc_init(vg->cmd, vg->cmd->mem, segtype, alloc,
+	if (!(ah = _alloc_init(vg->cmd, vg->cmd->mem, segtype, alloc, approx_alloc,
 			       new_extents, mirrors, stripes, log_count,
 			       vg->extent_size, region_size,
 			       parallel_areas)))
@@ -2999,7 +3020,8 @@ int lv_extend(struct logical_volume *lv,
 	      uint32_t stripes, uint32_t stripe_size,
 	      uint32_t mirrors, uint32_t region_size,
 	      uint32_t extents, const char *thin_pool_name,
-	      struct dm_list *allocatable_pvs, alloc_policy_t alloc)
+	      struct dm_list *allocatable_pvs, alloc_policy_t alloc,
+	      int approx_alloc)
 {
 	int r = 1;
 	int log_count = 0;
@@ -3027,9 +3049,18 @@ int lv_extend(struct logical_volume *lv,
 
 	if (!(ah = allocate_extents(lv->vg, lv, segtype, stripes, mirrors,
 				    log_count, region_size, extents,
-				    allocatable_pvs, alloc, NULL)))
+				    allocatable_pvs, alloc, approx_alloc, NULL)))
 		return_0;
 
+	if (ah->approx_alloc) {
+		extents = ah->new_extents;
+		if (segtype_is_raid(segtype)) {
+			log_error("Extents before: %u", extents);
+			extents -= ah->log_len * ah->area_multiple;
+			log_error("Extents after : %u", extents);
+		}
+	}
+
 	if (segtype_is_thin_pool(segtype) || segtype_is_cache_pool(segtype)) {
 		if (lv->le_count) {
 			/* lv_resize abstracts properly _tdata */
@@ -3646,7 +3677,7 @@ static int _lvresize_poolmetadata(struct cmd_context *cmd, struct volume_group *
 		       seg_mirrors,
 		       mseg->region_size,
 		       lp->poolmetadataextents - lv->le_count, NULL,
-		       pvh, alloc))
+		       pvh, alloc, 0))
 		return_0;
 
 	return 1;
@@ -4159,7 +4190,7 @@ static struct logical_volume *_lvresize_volume(struct cmd_context *cmd,
 			      lp->stripes, lp->stripe_size,
 			      lp->mirrors, first_seg(lv)->region_size,
 			      lp->extents - lv->le_count, NULL,
-			      pvh, alloc))
+			      pvh, alloc, 0))
 		return_NULL;
 
 	if (lock_lv) {
@@ -5596,7 +5627,7 @@ static struct logical_volume *_create_virtual_origin(struct cmd_context *cmd,
 		return_NULL;
 
 	if (!lv_extend(lv, segtype, 1, 0, 1, 0, voriginextents,
-		       NULL, NULL, ALLOC_INHERIT))
+		       NULL, NULL, ALLOC_INHERIT, 0))
 		return_NULL;
 
 	/* store vg on disk(s) */
@@ -6110,7 +6141,7 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg,
 		       (seg_is_thin_pool(lp) || seg_is_cache_pool(lp)) ?
 		       lp->poolmetadataextents : lp->region_size,
 		       seg_is_thin_volume(lp) ? lp->voriginextents : lp->extents,
-		       thin_name, lp->pvh, lp->alloc))
+		       thin_name, lp->pvh, lp->alloc, lp->approx_alloc))
 		return_NULL;
 
 	if (seg_is_cache_pool(lp)) {
diff --git a/lib/metadata/metadata-exported.h b/lib/metadata/metadata-exported.h
index faa82172d..6ca430980 100644
--- a/lib/metadata/metadata-exported.h
+++ b/lib/metadata/metadata-exported.h
@@ -672,7 +672,8 @@ int lv_extend(struct logical_volume *lv,
 	      uint32_t stripes, uint32_t stripe_size,
 	      uint32_t mirrors, uint32_t region_size,
 	      uint32_t extents, const char *thin_pool_name,
-	      struct dm_list *allocatable_pvs, alloc_policy_t alloc);
+	      struct dm_list *allocatable_pvs, alloc_policy_t alloc,
+	      int approx_alloc);
 
 /* lv must be part of lv->vg->lvs */
 int lv_remove(struct logical_volume *lv);
@@ -810,6 +811,7 @@ struct lvcreate_params {
 
 	uint32_t permission; /* all */
 	uint32_t read_ahead; /* all */
+	int approx_alloc;     /* all */
 	alloc_policy_t alloc; /* all */
 
 	struct dm_list tags;	/* all */
diff --git a/lib/metadata/mirror.c b/lib/metadata/mirror.c
index 5d99c50e7..86ec4ca88 100644
--- a/lib/metadata/mirror.c
+++ b/lib/metadata/mirror.c
@@ -1676,7 +1676,7 @@ int add_mirrors_to_segments(struct cmd_context *cmd, struct logical_volume *lv,
 							   region_size);
 
 	if (!(ah = allocate_extents(lv->vg, NULL, segtype, 1, mirrors, 0, 0,
-				    lv->le_count, allocatable_pvs, alloc,
+				    lv->le_count, allocatable_pvs, alloc, 0,
 				    parallel_areas))) {
 		log_error("Unable to allocate mirror extents for %s.", lv->name);
 		return 0;
@@ -1944,7 +1944,7 @@ int add_mirror_log(struct cmd_context *cmd, struct logical_volume *lv,
 	ah = allocate_extents(lv->vg, NULL, segtype,
 			      0, 0, log_count - old_log_count, region_size,
 			      lv->le_count, allocatable_pvs,
-			      alloc, parallel_areas);
+			      alloc, 0, parallel_areas);
 	if (!ah) {
 		log_error("Unable to allocate extents for mirror log.");
 		return 0;
@@ -2008,7 +2008,7 @@ int add_mirror_images(struct cmd_context *cmd, struct logical_volume *lv,
 
 	ah = allocate_extents(lv->vg, NULL, segtype,
 			      stripes, mirrors, log_count, region_size, lv->le_count,
-			      allocatable_pvs, alloc, parallel_areas);
+			      allocatable_pvs, alloc, 0, parallel_areas);
 	if (!ah) {
 		log_error("Unable to allocate extents for mirror(s).");
 		return 0;
diff --git a/lib/metadata/raid_manip.c b/lib/metadata/raid_manip.c
index 3f2b0439b..d1759aebf 100644
--- a/lib/metadata/raid_manip.c
+++ b/lib/metadata/raid_manip.c
@@ -419,7 +419,7 @@ static int _alloc_image_components(struct logical_volume *lv,
 
 	if (!(ah = allocate_extents(lv->vg, NULL, segtype, 0, count, count,
 				    region_size, extents, pvs,
-				    lv->alloc, parallel_areas)))
+				    lv->alloc, 0, parallel_areas)))
 		return_0;
 
 	for (s = 0; s < count; s++) {
@@ -483,7 +483,7 @@ static int _alloc_rmeta_for_lv(struct logical_volume *data_lv,
 	if (!(ah = allocate_extents(data_lv->vg, NULL, seg->segtype, 0, 1, 0,
 				    seg->region_size,
 				    1 /*RAID_METADATA_AREA_LEN*/,
-				    &allocatable_pvs, data_lv->alloc, NULL)))
+				    &allocatable_pvs, data_lv->alloc, 0, NULL)))
 		return_0;
 
 	if (!_alloc_image_component(data_lv, base_name, ah, 0,
diff --git a/lib/metadata/thin_manip.c b/lib/metadata/thin_manip.c
index c3f8e5683..1ae893a09 100644
--- a/lib/metadata/thin_manip.c
+++ b/lib/metadata/thin_manip.c
@@ -677,7 +677,7 @@ int handle_pool_metadata_spare(struct volume_group *vg, uint32_t extents,
 		       seg_mirrors,
 		       seg->region_size,
 		       extents - lv->le_count, NULL,
-		       pvh, lv->alloc))
+		       pvh, lv->alloc, 0))
 		return_0;
 
 	return 1;
diff --git a/test/shell/lvcreate-raid.sh b/test/shell/lvcreate-raid.sh
index 214b162d6..2a1ed6d4c 100644
--- a/test/shell/lvcreate-raid.sh
+++ b/test/shell/lvcreate-raid.sh
@@ -70,3 +70,87 @@ for i in raid4 \
 	aux wait_for_sync $vg $lv1
 	lvremove -ff $vg
 done
+
+# Create RAID using 100%FREE
+############################
+# 6 PVs with 18.5m in each PV.
+# 1 metadata LV = 1 extent   = .5m
+# 1 image = 36+37+37 extents = 55.00m = lv_size
+lvcreate --type raid1 -m 1 -l 100%FREE -n raid1 $vg
+check lv_field $vg/raid1 size "55.00m"
+lvremove -ff $vg
+
+# 1 metadata LV = 1 extent
+# 1 image = 36 extents
+# 5 images = 180 extents = 90.00m = lv_size
+lvcreate --type raid5 -i 5 -l 100%FREE -n raid5 $vg
+check lv_field $vg/raid5 size "90.00m"
+lvremove -ff $vg
+
+# 1 image = 36+37 extents
+# 2 images = 146 extents = 73.00m = lv_size
+lvcreate --type raid5 -i 2 -l 100%FREE -n raid5 $vg
+check lv_field $vg/raid5 size "73.00m"
+lvremove -ff $vg
+
+# 1 image = 36 extents
+# 4 images = 144 extents = 72.00m = lv_size
+lvcreate --type raid6 -i 4 -l 100%FREE -n raid6 $vg
+check lv_field $vg/raid6 size "72.00m"
+lvremove -ff $vg
+
+# Eat 18 of 37 extents from dev1, leaving 19
+lvcreate -l 18 -n lv $vg $dev1
+# Using 100% free should take the rest of dev1 and equal from dev2
+# 1 meta takes 1 extent
+# 1 image = 18 extents = 9.00m = lv_size
+lvcreate --type raid1 -m 1 -l 100%FREE -n raid1 $vg $dev1 $dev2
+check lv_field $vg/raid1 size "9.00m"
+# Ensure image size is the same as the RAID1 size
+check lv_field $vg/raid1 size `lvs --noheadings -o size $vg/raid1_rimage_0`
+# Amount remaining in dev2 should equal the amount taken by 'lv' in dev1
+check pv_field "$dev2" pv_free `lvs --noheadings -o size $vg/lv`
+lvremove -ff $vg
+
+# Eat 18 of 37 extents from dev1, leaving 19
+lvcreate -l 18 -n lv $vg $dev1
+# Using 100% free should take the rest of dev1 and equal amount from the rest
+# 1 meta takes 1 extent
+# 1 image = 18 extents = 9.00m
+# 5 images = 90 extents = 45.00m = lv_size
+lvcreate --type raid5 -i 5 -l 100%FREE -n raid5 $vg
+check lv_field $vg/raid5 size "45.00m"
+# Amount remaining in dev6 should equal the amount taken by 'lv' in dev1
+check pv_field "$dev6" pv_free `lvs --noheadings -o size $vg/lv`
+lvremove -ff $vg
+
+# Eat 18 of 37 extents from dev1, leaving 19
+lvcreate -l 18 -n lv $vg $dev1
+# Using 100% free should take the rest of dev1, an equal amount
+# from 2 more devs, and all extents from 3 additional devs
+# 1 meta takes 1 extent
+# 1 image = 18+37 extents
+# 2 images = 110 extents = 55.00m = lv_size
+lvcreate --type raid5 -i 2 -l 100%FREE -n raid5 $vg
+check lv_field $vg/raid5 size "55.00m"
+lvremove -ff $vg
+
+# Let's do some stripe tests too
+# Eat 18 of 37 extents from dev1, leaving 19
+lvcreate -l 18 -n lv $vg $dev1
+# Using 100% free should take the rest of dev1 and an equal amount from rest
+# 1 image = 19 extents
+# 6 images = 114 extents = 57.00m = lv_size
+lvcreate -i 6 -l 100%FREE -n stripe $vg
+check lv_field $vg/stripe size "57.00m"
+lvremove -ff $vg
+
+# Eat 18 of 37 extents from dev1, leaving 19
+lvcreate -l 18 -n lv $vg $dev1
+# Using 100% free should take the rest of dev1, an equal amount from
+#  one more dev, and all of the remaining 4
+# 1 image = 19+37+37 extents
+# 2 images = 186 extents = 93.00m = lv_size
+lvcreate -i 2 -l 100%FREE -n stripe $vg
+check lv_field $vg/stripe size "93.00m"
+lvremove -ff $vg
diff --git a/test/shell/lvcreate-raid10.sh b/test/shell/lvcreate-raid10.sh
index 143e86987..0ee18b811 100644
--- a/test/shell/lvcreate-raid10.sh
+++ b/test/shell/lvcreate-raid10.sh
@@ -46,6 +46,14 @@ aux wait_for_sync $vg $lv2
 
 lvremove -ff $vg
 
+# Test 100%FREE option
+# 37 extents / device
+# 1 image = 36 extents (1 for meta)
+# 3 images = 108 extents = 54.00m
+lvcreate --type raid10 -i 3 -l 100%FREE -n raid10 $vg
+check lv_field $vg/raid10 size "54.00m"
+lvremove -ff $vg
+
 #
 # FIXME: Add tests that specify particular PVs to use for creation
 #
diff --git a/tools/lvcreate.c b/tools/lvcreate.c
index bf719fe43..b413f3484 100644
--- a/tools/lvcreate.c
+++ b/tools/lvcreate.c
@@ -363,6 +363,8 @@ static int _update_extents_params(struct volume_group *vg,
 	} else
 		lp->pvh = &vg->pvs;
 
+	if (lcp->percent)
+		lp->approx_alloc = 1;
 	switch(lcp->percent) {
 		case PERCENT_VG:
 			lp->extents = percent_of_extents(lp->extents, vg->extent_count, 0);