diff --git a/device_mapper/vdo/vdo_target.c b/device_mapper/vdo/vdo_target.c
index a8a753e39..cdd3dbe6d 100644
--- a/device_mapper/vdo/vdo_target.c
+++ b/device_mapper/vdo/vdo_target.c
@@ -28,7 +28,7 @@ bool dm_vdo_validate_target_params(const struct dm_vdo_target_params *vtp,
 	if ((vtp->minimum_io_size != (512 >> SECTOR_SHIFT)) &&
 	    (vtp->minimum_io_size != (4096 >> SECTOR_SHIFT))) {
 		log_error("VDO minimum io size %u is unsupported [512, 4096].",
-			  vtp->minimum_io_size);
+			  (vtp->minimum_io_size << SECTOR_SHIFT));
 		valid = false;
 	}
 
diff --git a/tools/toollib.c b/tools/toollib.c
index dcb6c8f4f..f854d17c5 100644
--- a/tools/toollib.c
+++ b/tools/toollib.c
@@ -1372,6 +1372,10 @@ int get_vdo_settings(struct cmd_context *cmd,
 			u |= VDO_CHANGE_ONLINE;
 	}
 
+	/* store size in sector units */
+	if (vtp->minimum_io_size >= 512)
+		vtp->minimum_io_size >>= SECTOR_SHIFT;
+
 	// validation of updated VDO option
 	if (!dm_vdo_validate_target_params(vtp, 0 /* vdo_size */))
 		goto_out;