diff --git a/nixos/tests/hadoop/hdfs.nix b/nixos/tests/hadoop/hdfs.nix
index 45206eefa6c2..31b02964b4c6 100644
--- a/nixos/tests/hadoop/hdfs.nix
+++ b/nixos/tests/hadoop/hdfs.nix
@@ -36,6 +36,7 @@ import ../make-test-python.nix (
         datanode =
           { pkgs, ... }:
           {
+            virtualisation.diskSize = 4096;
             services.hadoop = {
               inherit package;
               hdfs.datanode = {