diff --git a/buildbot/master/master.cfg b/buildbot/master/master.cfg
index 5fb7c09a..ab5db462 100644
--- a/buildbot/master/master.cfg
+++ b/buildbot/master/master.cfg
@@ -148,6 +148,7 @@ linux2_factory.addStep(steps.ShellCommand(command=["./mach", "test-wpt", "--proc
                                                    "--log-raw", "wpt_raw.log"],
                                           env=linux_headless_env,
                                           logfiles={"wpt_raw.log": "wpt_raw.log"}))
+linux2_factory.addStep(steps.ShellCommand(command=["gzip", "wpt_raw.log"], env=linux_headless_env))
 linux2_factory.addStep(steps.Compile(command=["./mach", "build-cef"], env=linux_headless_env))
 
 linux3_factory = util.BuildFactory()
@@ -157,6 +158,7 @@ linux3_factory.addStep(steps.ShellCommand(command=["./mach", "test-css", "--rele
                                                    "--log-raw", "wpt_raw.log"],
                                           env=linux_headless_env,
                                           logfiles={"wpt_raw.log": "wpt_raw.log"}))
+linux3_factory.addStep(steps.ShellCommand(command=["gzip", "wpt_raw.log"], env=linux_headless_env))
 
 
 task_limited_test_env = dict({'RUST_TEST_TASKS': '1'}, **mac_test_env)
@@ -171,6 +173,7 @@ mac1_factory.addStep(steps.ShellCommand(command=["./mach", "test-wpt", "--proces
                                            "--log-raw", "wpt_raw.log"],
                                   env=mac_test_env,
                                   logfiles={"wpt_raw.log": "wpt_raw.log"}))
+mac1_factory.addStep(steps.ShellCommand(command=["gzip", "wpt_raw.log"], env=mac_test_env))
 mac1_factory.addStep(steps.ShellCommand(command=["./mach", "test-unit"], env=mac_test_env))
 
 mac2_factory = util.BuildFactory()
@@ -187,6 +190,7 @@ mac3_factory.addStep(steps.ShellCommand(command=["./mach", "test-css", "--releas
                                            "--log-raw", "wpt_raw.log"],
                                   env=mac_test_env,
                                   logfiles={"wpt_raw.log": "wpt_raw.log"}))
+mac3_factory.addStep(steps.ShellCommand(command=["gzip", "wpt_raw.log"], env=mac_test_env))
 
 android_compile_env = dict({'ANDROID_SDK': '/home/servo/android-sdk-linux/',
                             'ANDROID_NDK': '/home/servo/android-ndk-r10c/',