diff --git a/tests/t4100-dvh-partition-limits.sh b/tests/t4100-dvh-partition-limits.sh
index a1bc69a..906f3df 100755
--- a/tests/t4100-dvh-partition-limits.sh
+++ b/tests/t4100-dvh-partition-limits.sh
@@ -37,8 +37,8 @@ mp=`pwd`/mount-point
 n=4096
 
 # create an XFS file system
-dd if=/dev/zero of=$fs bs=1MB count=2 seek=20 || fail=1
-mkfs.xfs -f -q $fs || fail=1
+dd if=/dev/null of=$fs bs=1MB seek=50 || fail=1
+mkfs.xfs -q -d file,size=50m,name=$fs || fail=1
 mkdir "$mp" || fail=1
 
 # Unmount upon interrupt, failure, etc., as well as upon normal completion.
diff --git a/tests/t4100-msdos-partition-limits.sh b/tests/t4100-msdos-partition-limits.sh
index 65bda25..2ff6d7a 100755
--- a/tests/t4100-msdos-partition-limits.sh
+++ b/tests/t4100-msdos-partition-limits.sh
@@ -37,8 +37,8 @@ mp=`pwd`/mount-point
 n=4096
 
 # create an XFS file system
-dd if=/dev/zero of=$fs bs=1MB count=2 seek=20 || fail=1
-mkfs.xfs -f -q $fs || fail=1
+dd if=/dev/null of=$fs bs=1MB seek=50 || fail=1
+mkfs.xfs -q -d file,size=50m,name=$fs || fail=1
 mkdir "$mp" || fail=1
 
 # Unmount upon interrupt, failure, etc., as well as upon normal completion.