diff --git a/test_harness.py b/test_harness.py
index 5a7f1a0..e826ffe 100644
--- a/test_harness.py
+++ b/test_harness.py
@@ -53,7 +53,7 @@ def _make_loopbacked_devices(num):
     return devices
 
 
-def _run_command(num_devices, command):
+def _run_command(namespace, num_devices, command):
     """
     Prepare devices and run command on devices.
 
@@ -61,6 +61,14 @@ def _run_command(num_devices, command):
     :param list command: the command to be run
     """
     devices = _make_loopbacked_devices(num_devices)
+    if namespace.log_level > 0:
+        for device in devices:
+            for option in ["--getss", "--getpbsz", "--getiomin", "--getioopt"]:
+                diagcmd = ["blockdev", option, device]
+                with subprocess.Popen(diagcmd, stdout=subprocess.PIPE) as proc:
+                    blockdevoutput = proc.stdout.readline().strip().decode("utf-8")
+                print(f"output of {diagcmd}: {blockdevoutput}")
+
     command = command + list(itertools.chain(*[["--disk", dev] for dev in devices]))
     subprocess.run(command, check=True)
 
@@ -77,7 +85,7 @@ def _run_stratisd_cert(namespace):
         )
         + ["-v"]
     )
-    _run_command(3, command)
+    _run_command(namespace, 3, command)
 
 
 def _run_stratis_cli_cert(namespace):
@@ -92,7 +100,7 @@ def _run_stratis_cli_cert(namespace):
         )
         + ["-v"]
     )
-    _run_command(3, command)
+    _run_command(namespace, 3, command)
 
 
 def _gen_parser():
@@ -119,6 +127,9 @@ def _gen_parser():
     stratisd_cert_parser.add_argument(
         "--verify-devices", help="Verify /dev/disk/by-id devices", action="store_true"
     )
+    stratisd_cert_parser.add_argument(
+        "--log-level", help="Log level", action="store", type=int
+    )
 
     stratisd_cert_parser.add_argument(
         "--highest-revision-number",