diff --git a/test/basetest/utils.py b/test/basetest/utils.py
index 12e5bd975..8537815a2 100644
--- a/test/basetest/utils.py
+++ b/test/basetest/utils.py
@@ -249,7 +249,6 @@ def run_cmd_wait(cmd, input=None, stdout=PIPE, stderr=PIPE,
             "stdin": stdin,
             "stdout": stdout,
             "stderr": stderr,
-            "bufsize": 1,
             "close_fds": ON_POSIX,
             "env": env,
         },