diff --git a/tests/generic/256 b/tests/generic/256
index 4a53da87..cfe72371 100755
--- a/tests/generic/256
+++ b/tests/generic/256
@@ -165,7 +165,7 @@ _test_full_fs_punch()
 
 # Make a small file system to fill
 umount $SCRATCH_DEV &> /dev/null
-_scratch_mkfs_sized $(( 1024 * 1024 * 1024 )) &> /dev/null
+_scratch_mkfs_sized $(( 1536 * 1024 * 1024 )) &> /dev/null
 _scratch_mount
 # Test must be able to write files with non-root permissions
 chmod 777 $SCRATCH_MNT