diff --git a/conf/views.py b/conf/views.py
index 3b5f4cf..875832d 100644
--- a/conf/views.py
+++ b/conf/views.py
@@ -123,7 +123,10 @@ class JudgeServerAPI(APIView):
     @validate_serializer(EditJudgeServerSerializer)
     @super_admin_required
     def put(self, request):
-        JudgeServer.objects.filter(id=request.data["id"]).update(is_disabled=request.data["is_disabled"])
+        is_disabled = request.data.get("is_disabled", False)
+        JudgeServer.objects.filter(id=request.data["id"]).update(is_disabled=is_disabled)
+        if not is_disabled:
+            process_pending_task()
         return self.success()
 
 
diff --git a/deploy/entrypoint.sh b/deploy/entrypoint.sh
index ee7e46d..fdc589e 100755
--- a/deploy/entrypoint.sh
+++ b/deploy/entrypoint.sh
@@ -52,6 +52,7 @@ do
     python manage.py migrate --no-input &&
     python manage.py inituser --username=root --password=rootroot --action=create_super_admin &&
     echo "from options.options import SysOptions; SysOptions.judge_server_token='$JUDGE_SERVER_TOKEN'" | python manage.py shell &&
+    echo "from conf.models import JudgeServer; JudgeServer.objects.update(task_number=0)" | python manage.py shell &&
     break
     n=$(($n+1))
     echo "Failed to migrate, going to retry..."
diff --git a/deploy/nginx/locations.conf b/deploy/nginx/locations.conf
index a096ffa..da7fa38 100644
--- a/deploy/nginx/locations.conf
+++ b/deploy/nginx/locations.conf
@@ -6,11 +6,6 @@ location /api {
     include api_proxy.conf;
 }
 
-location /data/ {
-    internal;
-    alias /data/; # note that trailing slash
-}
-
 location /admin {
     root /app/dist/admin;
     try_files $uri $uri/ /index.html =404;
diff --git a/judge/dispatcher.py b/judge/dispatcher.py
index 0e14a19..c448095 100644
--- a/judge/dispatcher.py
+++ b/judge/dispatcher.py
@@ -48,18 +48,18 @@ class DispatcherBase(object):
         with transaction.atomic():
             servers = JudgeServer.objects.select_for_update().filter(is_disabled=False).order_by("task_number")
             servers = [s for s in servers if s.status == "normal"]
-            if servers:
-                server = servers[0]
-                server.used_instance_number = F("task_number") + 1
-                server.save()
-                return server
+            for server in servers:
+                if server.task_number <= server.cpu_core * 2:
+                    server.task_number = F("task_number") + 1
+                    server.save()
+                    return server
 
     @staticmethod
     def release_judge_server(judge_server_id):
         with transaction.atomic():
             # 使用原子操作, 同时因为use和release中间间隔了判题过程,需要重新查询一下
             server = JudgeServer.objects.get(id=judge_server_id)
-            server.used_instance_number = F("task_number") - 1
+            server.task_number = F("task_number") - 1
             server.save()
 
 
diff --git a/problem/views/admin.py b/problem/views/admin.py
index 7a71920..549f068 100644
--- a/problem/views/admin.py
+++ b/problem/views/admin.py
@@ -2,26 +2,24 @@ import hashlib
 import json
 import os
 import shutil
-import zipfile
 import tempfile
+import zipfile
 from wsgiref.util import FileWrapper
 
 from django.conf import settings
-from django.http import StreamingHttpResponse, HttpResponse, FileResponse
 from django.db import transaction
+from django.http import StreamingHttpResponse, FileResponse
 
 from account.decorators import problem_permission_required, ensure_created_by
+from contest.models import Contest, ContestStatus
+from fps.parser import FPSHelper, FPSParser
 from judge.dispatcher import SPJCompiler
 from judge.languages import language_names
-from contest.models import Contest, ContestStatus
 from submission.models import Submission, JudgeStatus
-from fps.parser import FPSHelper, FPSParser
 from utils.api import APIView, CSRFExemptAPIView, validate_serializer, APIError
+from utils.constants import Difficulty
 from utils.shortcuts import rand_str, natural_sort_key
 from utils.tasks import delete_files
-from utils.constants import Difficulty
-
-from ..utils import TEMPLATE_BASE, build_problem_template
 from ..models import Problem, ProblemRuleType, ProblemTag
 from ..serializers import (CreateContestProblemSerializer, CompileSPJSerializer,
                            CreateProblemSerializer, EditProblemSerializer, EditContestProblemSerializer,
@@ -29,6 +27,7 @@ from ..serializers import (CreateContestProblemSerializer, CompileSPJSerializer,
                            AddContestProblemSerializer, ExportProblemSerializer,
                            ExportProblemRequestSerialzier, UploadProblemForm, ImportProblemSerializer,
                            FPSProblemSerializer)
+from ..utils import TEMPLATE_BASE, build_problem_template
 
 
 class TestCaseZipProcessor(object):
@@ -137,12 +136,8 @@ class TestCaseAPI(CSRFExemptAPIView, TestCaseZipProcessor):
         with zipfile.ZipFile(file_name, "w") as file:
             for test_case in name_list:
                 file.write(f"{test_case_dir}/{test_case}", test_case)
-        if os.environ.get("OJ_ENV") == "production":
-            response = HttpResponse()
-            response["X-Accel-Redirect"] = file_name
-        else:
-            response = StreamingHttpResponse(FileWrapper(open(file_name, "rb")),
-                                             content_type="application/octet-stream")
+        response = StreamingHttpResponse(FileWrapper(open(file_name, "rb")),
+                                         content_type="application/octet-stream")
 
         response["Content-Disposition"] = f"attachment; filename=problem_{problem.id}_test_cases.zip"
         response["Content-Length"] = os.path.getsize(file_name)