diff --git a/instances/test_clone_disks.py b/instances/test_clone_disks.py
new file mode 100644
index 00000000..5c2a60e1
--- /dev/null
+++ b/instances/test_clone_disks.py
@@ -0,0 +1,54 @@
+"""A clone copies the disks of the VM's persistent definition: its quota and
+disk names come from those, not from the running VM's disks."""
+from unittest.mock import PropertyMock, patch
+
+from django.contrib.auth import get_user_model
+from django.contrib.auth.models import Permission
+from django.test import TestCase
+from django.urls import reverse
+
+from accounts.models import UserInstance
+from appsettings.models import AppSettings
+from computes.models import Compute
+from instances.models import Instance
+
+LIVE = [{"dev": "vda", "path": "/pool/live.qcow2", "storage": "pool", "image": "live.qcow2", "size": 1 << 30}]
+SAVED = [{"dev": "vdb", "path": "/pool/saved.qcow2", "storage": "pool", "image": "saved.qcow2", "size": 20 << 30}]
+
+
+class CloneDisksTestCase(TestCase):
+    def setUp(self):
+        compute = Compute.objects.create(name="cd", hostname="192.0.2.5", login="root", password="", type=1)
+        self.vm = Instance.objects.create(compute=compute, name="cd-vm", uuid="12345678-aaaa-bbbb-cccc-1234567890ab")
+
+    def clone(self, user, **post):
+        self.client.force_login(user)
+        with patch("instances.models.wvmInstance") as wvm, patch.object(
+            Compute, "status", new_callable=PropertyMock, return_value=True
+        ), patch("instances.views.utils.check_user_quota", return_value="") as quota:
+            wvm.return_value.get_disk_devices.side_effect = lambda config=False: SAVED if config else LIVE
+            wvm.return_value.get_vcpu.return_value = 1
+            wvm.return_value.get_memory.return_value = 512
+            wvm.return_value.get_net_devices.return_value = []
+            wvm.return_value.clone_instance.return_value = "abcdefab-0000-1111-2222-333333333333"
+            response = self.client.post(reverse("instances:clone", args=[self.vm.id]), post)
+            self.messages = [str(m) for m in response.wsgi_request._messages]
+        return quota, wvm.return_value.clone_instance
+
+    def test_the_quota_counts_the_disks_the_clone_copies(self):
+        owner = get_user_model().objects.create_user("cd_owner", password="x")
+        owner.user_permissions.add(Permission.objects.get(codename="clone_instances"))
+        UserInstance.objects.create(instance=self.vm, user=owner, is_change=True)
+        quota, _ = self.clone(owner, name="cd-clone")
+        self.assertEqual(quota.call_args.args[4], 20)
+
+    def test_automatic_disk_names_are_for_the_disks_the_clone_copies(self):
+        admin = get_user_model().objects.create_superuser("cd_admin", "cd@example.com", "x")
+        AppSettings.objects.filter(key="CLONE_INSTANCE_AUTO_NAME").update(value="True")
+        with patch("instances.views.utils.get_clone_free_names", return_value=["auto-1"]), patch(
+            "instances.views.utils.get_dhcp_mac_address", return_value="52:54:00:00:00:01"
+        ):
+            _, clone_instance = self.clone(admin)
+        data = clone_instance.call_args.args[0]
+        self.assertIn("disk-vdb", data)
+        self.assertNotIn("disk-vda", data)
diff --git a/instances/views.py b/instances/views.py
index 8f6579f2..d95aa9ab 100755
--- a/instances/views.py
+++ b/instances/views.py
@@ -1784,7 +1784,8 @@ def _clone_plan(request, instance):
     clone_data["clone-title"] = request.POST.get("clone-title", "").strip()
     clone_data["clone-description"] = request.POST.get("clone-description", "").strip()
 
-    disk_sum = sum(int(disk.get("size") or 0) >> 30 for disk in instance.disks)
+    # the clone copies the disks of the persistent definition
+    disk_sum = sum(int(disk.get("size") or 0) >> 30 for disk in instance.config_disks)
     quota_msg = utils.check_user_quota(
         request.user, 1, instance.vcpu, instance.memory, disk_sum
     )
@@ -1803,7 +1804,7 @@ def _clone_plan(request, instance):
         auto_vname = utils.get_clone_free_names()[0]
         clone_data["name"] = auto_vname
         clone_data["clone-net-mac-0"] = utils.get_dhcp_mac_address(auto_vname)
-        for disk in instance.disks:
+        for disk in instance.config_disks:
             disk_dev = f"disk-{disk['dev']}"
             disk_name = utils.get_clone_disk_name(disk, instance.name, auto_vname)
             clone_data[disk_dev] = disk_name