diff --git a/lib/display/display.c b/lib/display/display.c
index df21009a4..31d62d533 100644
--- a/lib/display/display.c
+++ b/lib/display/display.c
@@ -607,7 +607,7 @@ int lvdisplay_full(struct cmd_context *cmd,
 		log_print("LV Pool metadata       %s", seg->metadata_lv->name);
 		log_print("LV Pool data           %s", seg_lv(seg, 0)->name);
 		log_print("LV Pool chunk size     %s",
-			  display_size(cmd, seg->data_block_size));
+			  display_size(cmd, seg->chunk_size));
 		log_print("LV Zero new blocks     %s",
 			  seg->zero_new_blocks ? "yes" : "no");
 	}
diff --git a/lib/metadata/lv.c b/lib/metadata/lv.c
index 1c72cdee7..7cb154622 100644
--- a/lib/metadata/lv.c
+++ b/lib/metadata/lv.c
@@ -126,7 +126,7 @@ uint64_t lvseg_chunksize(const struct lv_segment *seg)
 	if (lv_is_cow(seg->lv))
 		size = (uint64_t) find_cow(seg->lv)->chunk_size;
 	else if (lv_is_thin_pool(seg->lv))
-		size = (uint64_t) seg->data_block_size;
+		size = (uint64_t) seg->chunk_size;
 	else
 		size = UINT64_C(0);
 
diff --git a/lib/metadata/lv_manip.c b/lib/metadata/lv_manip.c
index 07cfcbaf8..e14884d9b 100644
--- a/lib/metadata/lv_manip.c
+++ b/lib/metadata/lv_manip.c
@@ -2060,7 +2060,7 @@ int lv_add_virtual_segment(struct logical_volume *lv, uint64_t status,
 			return 0;
 		}
 		thin_pool_lv = lvl->lv;
-		size = first_seg(thin_pool_lv)->data_block_size;
+		size = first_seg(thin_pool_lv)->chunk_size;
 		if (lv->vg->extent_size < size) {
 			/* Align extents on chunk boundary size */
 			size = ((uint64_t)lv->vg->extent_size * extents + size - 1) /
@@ -4290,7 +4290,7 @@ static struct logical_volume *_lv_create_an_lv(struct volume_group *vg, struct l
 
 	if (seg_is_thin_pool(lp)) {
 		first_seg(lv)->zero_new_blocks = lp->zero ? 1 : 0;
-		first_seg(lv)->data_block_size = lp->chunk_size;
+		first_seg(lv)->chunk_size = lp->chunk_size;
 		/* FIXME: use lowwatermark  via lvm.conf global for all thinpools ? */
 		first_seg(lv)->low_water_mark = 0;
 	} else if (seg_is_thin_volume(lp)) {
diff --git a/lib/metadata/merge.c b/lib/metadata/merge.c
index 527488e6b..2da81522c 100644
--- a/lib/metadata/merge.c
+++ b/lib/metadata/merge.c
@@ -202,10 +202,10 @@ int check_lv_segments(struct logical_volume *lv, int complete_vg)
 					inc_error_count;
 				}
 
-				if (seg->data_block_size < DM_THIN_MIN_DATA_BLOCK_SIZE ||
-				    seg->data_block_size > DM_THIN_MAX_DATA_BLOCK_SIZE) {
-					log_error("LV %s: thin pool segment %u  data block size %d is out of range",
-						  lv->name, seg_count, seg->data_block_size);
+				if (seg->chunk_size < DM_THIN_MIN_DATA_BLOCK_SIZE ||
+				    seg->chunk_size > DM_THIN_MAX_DATA_BLOCK_SIZE) {
+					log_error("LV %s: thin pool segment %u  chunk size %d is out of range",
+						  lv->name, seg_count, seg->chunk_size);
 					inc_error_count;
 				}
 			} else {
diff --git a/lib/metadata/metadata-exported.h b/lib/metadata/metadata-exported.h
index 941e710f5..9cfe5c7c1 100644
--- a/lib/metadata/metadata-exported.h
+++ b/lib/metadata/metadata-exported.h
@@ -331,7 +331,8 @@ struct lv_segment {
 	uint32_t stripe_size;	/* For stripe and RAID - in sectors */
 	uint32_t area_count;
 	uint32_t area_len;
-	uint32_t chunk_size;	/* For snapshots - in sectors */
+	uint32_t chunk_size;	/* For snapshots/thin_pool.  In sectors. */
+				/* For thin_pool, 128..2097152. */
 	struct logical_volume *origin;	/* snap and thin */
 	struct logical_volume *cow;
 	struct dm_list origin_list;
@@ -348,7 +349,6 @@ struct lv_segment {
 	struct logical_volume *metadata_lv;	/* For thin_pool */
 	uint64_t transaction_id;		/* For thin_pool, thin */
 	uint64_t low_water_mark;		/* For thin_pool */
-	uint32_t data_block_size;		/* For thin_pool, 128..2097152 */
 	unsigned zero_new_blocks;		/* For thin_pool */
 	struct dm_list thin_messages;		/* For thin_pool */
 	struct logical_volume *pool_lv;		/* For thin */
diff --git a/lib/thin/thin.c b/lib/thin/thin.c
index 7fbf43b97..629c5a538 100644
--- a/lib/thin/thin.c
+++ b/lib/thin/thin.c
@@ -115,16 +115,16 @@ static int _thin_pool_text_import(struct lv_segment *seg,
 	if (!dm_config_get_uint64(sn, "transaction_id", &seg->transaction_id))
 		return SEG_LOG_ERROR("Could not read transaction_id for");
 
-	if (!dm_config_get_uint32(sn, "data_block_size", &seg->data_block_size))
-		return SEG_LOG_ERROR("Could not read data_block_size");
+	if (!dm_config_get_uint32(sn, "chunk_size", &seg->chunk_size))
+		return SEG_LOG_ERROR("Could not read chunk_size");
 
 	if (dm_config_has_node(sn, "low_water_mark") &&
 	    !dm_config_get_uint64(sn, "low_water_mark", &seg->low_water_mark))
 		return SEG_LOG_ERROR("Could not read low_water_mark");
 
-	if ((seg->data_block_size < DM_THIN_MIN_DATA_BLOCK_SIZE) ||
-	    (seg->data_block_size > DM_THIN_MAX_DATA_BLOCK_SIZE))
-		return SEG_LOG_ERROR("Unsupported value %u for data_block_size",
+	if ((seg->chunk_size < DM_THIN_MIN_DATA_BLOCK_SIZE) ||
+	    (seg->chunk_size > DM_THIN_MAX_DATA_BLOCK_SIZE))
+		return SEG_LOG_ERROR("Unsupported value %u for chunk_size",
 				     seg->device_id);
 
 	if (dm_config_has_node(sn, "zero_new_blocks") &&
@@ -155,9 +155,8 @@ static int _thin_pool_text_export(const struct lv_segment *seg, struct formatter
 	outf(f, "metadata = \"%s\"", seg->metadata_lv->name);
 	outf(f, "pool = \"%s\"", seg_lv(seg, 0)->name);
 	outf(f, "transaction_id = %" PRIu64, seg->transaction_id);
-// FIXME  maybe switch to use  chunksize (as with snapshot ??)
-	outsize(f, (uint64_t) seg->data_block_size,
-		"data_block_size = %u", seg->data_block_size);
+	outsize(f, (uint64_t) seg->chunk_size,
+		"chunk_size = %u", seg->chunk_size);
 
 	if (seg->low_water_mark)
 		outf(f, "low_water_mark = %" PRIu64, seg->low_water_mark);
@@ -254,7 +253,7 @@ static int _thin_pool_add_target_line(struct dev_manager *dm,
 
 	if (!dm_tree_node_add_thin_pool_target(node, len, seg->transaction_id,
 					       metadata_dlid, pool_dlid,
-					       seg->data_block_size, seg->low_water_mark,
+					       seg->chunk_size, seg->low_water_mark,
 					       seg->zero_new_blocks ? 0 : 1))
 		return_0;