diff --git a/lisa/microsoft/testsuites/cpu/cpusuite.py b/lisa/microsoft/testsuites/cpu/cpusuite.py
index 08c8f93699..e43ea60dc1 100644
--- a/lisa/microsoft/testsuites/cpu/cpusuite.py
+++ b/lisa/microsoft/testsuites/cpu/cpusuite.py
@@ -98,9 +98,9 @@ def verify_cpu_hot_plug(self, log: Logger, node: Node) -> None:
     )
     def verify_cpu_offline_storage_workload(self, log: Logger, node: Node) -> None:
         # run fio process asynchronously on the node
-        fio_data_size_in_gb = 1
+        fio_data_size_in_mb = 1
         try:
-            image_folder_path = node.find_partition_with_freespace(fio_data_size_in_gb)
+            image_folder_path = node.find_partition_with_freespace(fio_data_size_in_mb)
             # Each CPU takes ~10 seconds to toggle offline-online
             fio_run_time = 300 + (node.tools[Lscpu].get_thread_count() * 10)
             fio_process = node.tools[Fio].launch_async(
@@ -111,7 +111,7 @@ def verify_cpu_offline_storage_workload(self, log: Logger, node: Node) -> None:
                 numjob=10,
                 time=fio_run_time,
                 block_size="1M",
-                size_gb=fio_data_size_in_gb,
+                size_mb=fio_data_size_in_mb,
                 group_reporting=False,
                 overwrite=True,
                 time_based=True,
diff --git a/lisa/microsoft/testsuites/performance/common.py b/lisa/microsoft/testsuites/performance/common.py
index c7bf781aaa..a030ea9a6f 100644
--- a/lisa/microsoft/testsuites/performance/common.py
+++ b/lisa/microsoft/testsuites/performance/common.py
@@ -156,7 +156,7 @@ def perf_disk(
                 filename=filename,
                 mode=mode.name,
                 time=time,
-                size_gb=size_mb,
+                size_mb=size_mb,
                 block_size=f"{block_size}K",
                 iodepth=iodepth,
                 overwrite=overwrite,
diff --git a/lisa/microsoft/testsuites/power/common.py b/lisa/microsoft/testsuites/power/common.py
index 947b85fd7e..ebbc1e376a 100644
--- a/lisa/microsoft/testsuites/power/common.py
+++ b/lisa/microsoft/testsuites/power/common.py
@@ -365,7 +365,7 @@ def run_storage_workload(node: Node) -> Decimal:
         time=120,
         block_size="1M",
         overwrite=True,
-        size_gb=1,
+        size_mb=1,
     )
     return fio_result.iops
 
diff --git a/lisa/microsoft/testsuites/storage/storagesuite.py b/lisa/microsoft/testsuites/storage/storagesuite.py
index 9f98eeaa59..110a05c569 100644
--- a/lisa/microsoft/testsuites/storage/storagesuite.py
+++ b/lisa/microsoft/testsuites/storage/storagesuite.py
@@ -153,7 +153,7 @@ def verify_disk_with_fio_verify_option(self, node: Node) -> None:
                     numjob=0,
                     time=0,
                     block_size="",
-                    size_gb=100,
+                    size_mb=100,
                     group_reporting=False,
                     do_verify=True,
                     bsrange="512-256K",
diff --git a/lisa/tools/fio.py b/lisa/tools/fio.py
index a184e6e918..c567bb9243 100644
--- a/lisa/tools/fio.py
+++ b/lisa/tools/fio.py
@@ -96,7 +96,7 @@ def launch(
         time: int = 120,
         ssh_timeout: int = 6400,
         block_size: str = "4K",
-        size_gb: int = 0,
+        size_mb: int = 0,
         direct: bool = True,
         gtod_reduce: bool = False,
         group_reporting: bool = True,
@@ -118,7 +118,7 @@ def launch(
             numjob,
             time,
             block_size,
-            size_gb,
+            size_mb,
             direct,
             gtod_reduce,
             group_reporting,
@@ -154,7 +154,7 @@ def launch_async(
         numjob: int,
         time: int = 120,
         block_size: str = "4K",
-        size_gb: int = 0,
+        size_mb: int = 0,
         direct: bool = True,
         gtod_reduce: bool = False,
         group_reporting: bool = True,
@@ -176,7 +176,7 @@ def launch_async(
             numjob,
             time,
             block_size,
-            size_gb,
+            size_mb,
             direct,
             gtod_reduce,
             group_reporting,
@@ -326,7 +326,7 @@ def _get_command(  # noqa: C901
         numjob: int = 0,
         time: int = 120,
         block_size: str = "4K",
-        size_gb: int = 0,
+        size_mb: int = 0,
         direct: bool = True,
         gtod_reduce: bool = False,
         group_reporting: bool = True,
@@ -358,8 +358,8 @@ def _get_command(  # noqa: C901
             cmd += " --direct=1"
         if gtod_reduce:
             cmd += " --gtod_reduce=1"
-        if size_gb:
-            cmd += f" --size={size_gb}M"
+        if size_mb:
+            cmd += f" --size={size_mb}M"
         if group_reporting:
             cmd += " --group_reporting"
         if overwrite: