diff --git a/cmd/ztest/ztest.c b/cmd/ztest/ztest.c
index 34bae1102b..026fe54170 100644
--- a/cmd/ztest/ztest.c
+++ b/cmd/ztest/ztest.c
@@ -175,7 +175,7 @@ static const ztest_shared_opts_t ztest_opts_defaults = {
 	.zo_mirrors = 2,
 	.zo_raidz = 4,
 	.zo_raidz_parity = 1,
-	.zo_vdev_size = SPA_MINDEVSIZE,
+	.zo_vdev_size = SPA_MINDEVSIZE * 2,
 	.zo_datasets = 7,
 	.zo_threads = 23,
 	.zo_passtime = 60,		/* 60 seconds */