diff --git a/Build.c b/Build.c
index 1e213ce..21fe2a5 100644
--- a/Build.c
+++ b/Build.c
@@ -36,7 +36,8 @@
 int Build(char *mddev, int mdfd, int chunk, int level, int layout,
 	  int raiddisks,
 	  mddev_dev_t devlist, int assume_clean,
-	  char *bitmap_file, int bitmap_chunk, int write_behind, int delay, int verbose)
+	  char *bitmap_file, int bitmap_chunk, int write_behind, int delay,
+	  int verbose, unsigned long long size)
 {
 	/* Build a linear or raid0 arrays without superblocks
 	 * We cannot really do any checks, we just do it.
@@ -57,7 +58,6 @@ int Build(char *mddev, int mdfd, int chunk, int level, int layout,
 	int subdevs = 0, missing_disks = 0;
 	mddev_dev_t dv;
 	int bitmap_fd;
-	unsigned long long size = ~0ULL;
 	unsigned long long bitmapsize;
 
 	/* scan all devices, make sure they really are block devices */
@@ -119,7 +119,7 @@ int Build(char *mddev, int mdfd, int chunk, int level, int layout,
 	if (vers >= 9000) {
 		mdu_array_info_t array;
 		array.level = level;
-		array.size = 0;
+		array.size = size;
 		array.nr_disks = raiddisks;
 		array.raid_disks = raiddisks;
 		array.md_minor = 0;
@@ -178,7 +178,7 @@ int Build(char *mddev, int mdfd, int chunk, int level, int layout,
 		    (size == 0 || dsize < size))
 				size = dsize;
 		close(fd);
-		if (vers>= 9000) {
+		if (vers >= 9000) {
 			mdu_disk_info_t disk;
 			disk.number = i;
 			disk.raid_disk = i;
diff --git a/mdadm.c b/mdadm.c
index 6609bf2..e889b9c 100644
--- a/mdadm.c
+++ b/mdadm.c
@@ -367,7 +367,8 @@ int main(int argc, char *argv[])
 
 
 		case O(GROW,'z'):
-		case O(CREATE,'z'): /* size */
+		case O(CREATE,'z'):
+		case O(BUILD,'z'): /* size */
 			if (size >= 0) {
 				fprintf(stderr, Name ": size may only be specified once. "
 					"Second value is %s.\n", optarg);
@@ -1161,7 +1162,8 @@ int main(int argc, char *argv[])
 		}
 		rv = Build(devlist->devname, mdfd, chunk, level, layout,
 			   raiddisks, devlist->next, assume_clean,
-			   bitmap_file, bitmap_chunk, write_behind, delay, verbose-quiet);
+			   bitmap_file, bitmap_chunk, write_behind, delay,
+			   verbose-quiet, size);
 		break;
 	case CREATE:
 		if (delay == 0) delay = DEFAULT_BITMAP_DELAY;
diff --git a/mdadm.h b/mdadm.h
index 0d5c721..0eb8f39 100644
--- a/mdadm.h
+++ b/mdadm.h
@@ -443,7 +443,8 @@ extern int Assemble(struct supertype *st, char *mddev, int mdfd,
 extern int Build(char *mddev, int mdfd, int chunk, int level, int layout,
 		 int raiddisks,
 		 mddev_dev_t devlist, int assume_clean,
-		 char *bitmap_file, int bitmap_chunk, int write_behind, int delay, int verbose);
+		 char *bitmap_file, int bitmap_chunk, int write_behind,
+		 int delay, int verbose, unsigned long long size);
 
 
 extern int Create(struct supertype *st, char *mddev, int mdfd,