diff --git a/WHATS_NEW b/WHATS_NEW
index 947fbfe64..adf3f64ab 100644
--- a/WHATS_NEW
+++ b/WHATS_NEW
@@ -1,5 +1,6 @@
 Version 2.01.15 - 
 =================================
+  Add format1 dev_write debug messages.
   Add clustered VG attribute to report.
   Move lvconvert parameters into struct lvconvert_params.
   Add clustered VG flag to LV lock requests.
diff --git a/lib/format1/disk-rep.c b/lib/format1/disk-rep.c
index 9418ff98b..cf305af05 100644
--- a/lib/format1/disk-rep.c
+++ b/lib/format1/disk-rep.c
@@ -506,6 +506,9 @@ static int _write_vgd(struct disk_list *data)
 	struct vg_disk *vgd = &data->vgd;
 	uint64_t pos = data->pvd.vg_on_disk.base;
 
+	log_debug("Writing %s VG metadata to %s at %" PRIu64 " len %" PRIsize_t,
+		  data->pvd.vg_name, dev_name(data->dev), pos, sizeof(*vgd));
+
 	_xlate_vgd(vgd);
 	if (!dev_write(data->dev, pos, sizeof(*vgd), vgd))
 		fail;
@@ -528,6 +531,10 @@ static int _write_uuids(struct disk_list *data)
 			return 0;
 		}
 
+		log_debug("Writing %s uuidlist to %s at %" PRIu64 " len %"
+			  PRIsize_t, data->pvd.vg_name, dev_name(data->dev),
+			  pos, NAME_LEN);
+
 		if (!dev_write(data->dev, pos, NAME_LEN, ul->uuid))
 			fail;
 
@@ -539,6 +546,10 @@ static int _write_uuids(struct disk_list *data)
 
 static int _write_lvd(struct device *dev, uint64_t pos, struct lv_disk *disk)
 {
+	log_debug("Writing %s LV %s metadata to %s at %" PRIu64 " len %"
+		  PRIsize_t, disk->vg_name, disk->lv_name, dev_name(dev),
+		  pos, sizeof(*disk));
+
 	_xlate_lvd(disk);
 	if (!dev_write(dev, pos, sizeof(*disk), disk))
 		fail;
@@ -581,6 +592,10 @@ static int _write_extents(struct disk_list *data)
 	struct pe_disk *extents = data->extents;
 	uint64_t pos = data->pvd.pe_on_disk.base;
 
+	log_debug("Writing %s extents metadata to %s at %" PRIu64 " len %"
+		  PRIsize_t, data->pvd.vg_name, dev_name(data->dev),
+		  pos, len);
+
 	_xlate_extents(extents, data->pvd.pe_total);
 	if (!dev_write(data->dev, pos, len, extents))
 		fail;
@@ -613,6 +628,10 @@ static int _write_pvd(struct disk_list *data)
 	memset(buf, 0, size);
 	memcpy(buf, &data->pvd, sizeof(struct pv_disk));
 
+	log_debug("Writing %s PV metadata to %s at %" PRIu64 " len %"
+		  PRIsize_t, data->pvd.vg_name, dev_name(data->dev),
+		  pos, size);
+
 	_xlate_pvd((struct pv_disk *) buf);
 	if (!dev_write(data->dev, pos, size, buf)) {
 		dbg_free(buf);