diff --git a/backend/conf/copr-be.conf.example b/backend/conf/copr-be.conf.example
index 6210e060d..4f6e88077 100644
--- a/backend/conf/copr-be.conf.example
+++ b/backend/conf/copr-be.conf.example
@@ -42,6 +42,10 @@ sleeptime=30
 # Maximum number of concurrently running tasks per architecture.
 #builds_max_workers_arch=x86_64=10,ppc64le=12
 
+# Maximum number of concurrent build workers per architecture and owner.  For
+# example, give at most 15 ppc64le and 10 s390x machines to one copr owner:
+#build_max_workers_arch_per_owner=ppc64le=15,s390x=10
+
 # Maximum number of concurrently running tasks per project owner.
 #builds_max_workers_owner=20
 
diff --git a/backend/copr-backend.spec b/backend/copr-backend.spec
index 6531349a8..e4ab4874c 100644
--- a/backend/copr-backend.spec
+++ b/backend/copr-backend.spec
@@ -6,7 +6,7 @@
 %global tests_version 4
 %global tests_tar test-data-copr-backend
 
-%global copr_common_version 0.16.4.dev
+%global copr_common_version 0.20.1.dev1
 
 Name:       copr-backend
 Version:    1.172
diff --git a/backend/copr_backend/daemons/build_dispatcher.py b/backend/copr_backend/daemons/build_dispatcher.py
index d074f0ff7..c2f05bebc 100644
--- a/backend/copr_backend/daemons/build_dispatcher.py
+++ b/backend/copr_backend/daemons/build_dispatcher.py
@@ -2,10 +2,11 @@
 BuildDispatcher related classes.
 """
 
-from copr_common.worker_manager import GroupWorkerLimit
+from copr_common.worker_manager import HashWorkerLimit
 from copr_backend.dispatcher import BackendDispatcher
 from copr_backend.rpm_builds import (
     ArchitectureWorkerLimit,
+    ArchitectureUserWorkerLimit,
     BuildTagLimit,
     RPMBuildWorkerManager,
     BuildQueueTask,
@@ -83,9 +84,14 @@ def __init__(self, backend_opts):
         super().__init__(backend_opts)
         self.max_workers = backend_opts.builds_max_workers
 
-        for tag_type in ["arch", "tag"]:
-            lclass = ArchitectureWorkerLimit if tag_type == "arch" else \
-                     BuildTagLimit
+        for tag_type in ["arch", "tag", "arch_per_owner"]:
+            match tag_type:
+                case "arch":
+                    lclass = ArchitectureWorkerLimit
+                case "tag":
+                    lclass = BuildTagLimit
+                case "arch_per_owner":
+                    lclass = ArchitectureUserWorkerLimit
             for tag, limit in backend_opts.builds_limits[tag_type].items():
                 self.log.info("setting %s(%s) limit to %s", tag_type, tag, limit)
                 self.limits.append(lclass(tag, limit))
@@ -93,7 +99,7 @@ def __init__(self, backend_opts):
         for limit_type in ['sandbox', 'owner']:
             max_builders = backend_opts.builds_limits[limit_type]
             self.log.info("setting %s limit to %s", limit_type, max_builders)
-            self.limits.append(GroupWorkerLimit(
+            self.limits.append(HashWorkerLimit(
                 lambda x, limit=limit_type: getattr(x, limit),
                 max_builders,
                 name=limit_type,
diff --git a/backend/copr_backend/helpers.py b/backend/copr_backend/helpers.py
index 05348366d..75fa5e62d 100644
--- a/backend/copr_backend/helpers.py
+++ b/backend/copr_backend/helpers.py
@@ -215,9 +215,9 @@ def _get_limits_conf(parser):
             "option.  Please use format: "
             "builds_max_workers_{0} = {1}1=COUNT,{1}2=COUNT")
     err2 = ("Duplicate left value '{}' in 'builds_max_workers_{}' configuration")
-    limits = {"arch": {}, "tag": {}}
+    limits = {"arch": {}, "tag": {}, "arch_per_owner": {}}
 
-    for config_type in ["arch", "tag"]:
+    for config_type in ["arch", "tag", "arch_per_owner"]:
         option = "builds_max_workers_{}".format(config_type)
         raw = _get_conf(parser, "backend", option, None)
         if raw:
diff --git a/backend/copr_backend/rpm_builds.py b/backend/copr_backend/rpm_builds.py
index 4694e3a63..af0ce5606 100644
--- a/backend/copr_backend/rpm_builds.py
+++ b/backend/copr_backend/rpm_builds.py
@@ -2,7 +2,11 @@
 Abstraction for RPM and SRPM builds on backend.
 """
 
-from copr_common.worker_manager import WorkerManager, PredicateWorkerLimit
+from copr_common.worker_manager import (
+    HashWorkerLimit,
+    WorkerManager,
+    PredicateWorkerLimit,
+)
 from copr_backend.worker_manager import BackendQueueTask
 from copr_backend.helpers import get_chroot_arch
 
@@ -133,6 +137,19 @@ def predicate(x):
         super().__init__(predicate, limit, name="arch_{}".format(architecture))
 
 
+class ArchitectureUserWorkerLimit(HashWorkerLimit):
+    """
+    Limit number of machines of specific architecture we give to a single
+    Copr owner (user or group).
+    """
+    def __init__(self, architecture, limit):
+        super().__init__(
+            lambda x: f"{x.requested_arch}_{x.owner}",
+            limit,
+            name=f"arch_{architecture}_owner",
+        )
+
+
 class BuildTagLimit(PredicateWorkerLimit):
     """
     Limit the amount of concurrently running builds per given build tag.
diff --git a/backend/tests/test_config_reader.py b/backend/tests/test_config_reader.py
index 5d525cbd2..2a7c338ed 100644
--- a/backend/tests/test_config_reader.py
+++ b/backend/tests/test_config_reader.py
@@ -37,7 +37,8 @@ def get_minimal_config_file(self):
     def test_minimal_file_and_defaults(self):
         opts = BackendConfigReader(self.get_minimal_config_file()).read()
         assert opts.destdir == "/tmp"
-        assert opts.builds_limits == {'arch': {}, 'tag': {}, 'owner': 20, 'sandbox': 10}
+        assert opts.builds_limits == {'arch': {}, 'tag': {}, 'owner': 20,
+                                      'sandbox': 10, 'arch_per_owner': {}}
 
     def test_correct_build_limits(self):
         opts = BackendConfigReader(
@@ -48,6 +49,7 @@ def test_correct_build_limits(self):
                     "builds_max_workers_tag = Power9=9\n"
                     "builds_max_workers_owner = 5\n"
                     "builds_max_workers_sandbox = 3\n"
+                    "builds_max_workers_arch_per_owner = ppc64le=11, s390x=5\n"
                 ))).read()
         assert opts.builds_limits == {
             'arch': {
@@ -58,7 +60,11 @@ def test_correct_build_limits(self):
                 'Power9': 9,
             },
             'owner': 5,
-            'sandbox': 3
+            'sandbox': 3,
+            'arch_per_owner': {
+                'ppc64le': 11,
+                's390x': 5,
+            },
         }
 
     @pytest.mark.parametrize("broken_config", [
diff --git a/backend/tests/test_worker_limits.py b/backend/tests/test_worker_limits.py
index 742bfa872..f63ffacce 100644
--- a/backend/tests/test_worker_limits.py
+++ b/backend/tests/test_worker_limits.py
@@ -5,13 +5,14 @@
 # pylint: disable=protected-access
 
 from copr_common.worker_manager import (
-    GroupWorkerLimit,
+    HashWorkerLimit,
     PredicateWorkerLimit,
     StringCounter,
 )
 from copr_backend.worker_manager import BackendQueueTask
 from copr_backend.rpm_builds import (
     ArchitectureWorkerLimit,
+    ArchitectureUserWorkerLimit,
     BuildTagLimit,
     BuildQueueTask,
 )
@@ -23,16 +24,19 @@
 }, {
     "build_id": 7,
     "task_id": "7-fedora-rawhide-x86_64",
+    "chroot": "fedora-rawhide-x86_64",
     "project_owner": "cecil",
     "sandbox": "sb1",
 }, {
     "build_id": 4,
     "task_id": "7-fedora-32-x86_64",
+    "chroot": "fedora-32-x86_64",
     "project_owner": "bedrich",
     "sandbox": "sb2",
 }, {
     "build_id": 4,
     "task_id": "7-fedora-31-x86_64",
+    "chroot": "fedora-31-x86_64",
     "project_owner": "bedrich",
     "sandbox": "sb2",
     "tags": ["special_requirement"],
@@ -89,7 +93,7 @@ def test_predicate_worker_limit_sometimes():
     assert wl.check(_QT(5)) is False
 
 def test_group_worker_limit():
-    wl = GroupWorkerLimit(lambda x: x.group, 2)
+    wl = HashWorkerLimit(lambda x: x.group, 2)
     for _ in ["first", "cleared", "cleared"]:
         for task in [0, 1, 2]:
             wl.worker_added(str(task), _QT(str(task)))
@@ -111,10 +115,11 @@ def test_worker_limit_info():
     limits = [
         PredicateWorkerLimit(lambda _: True, 8),
         PredicateWorkerLimit(lambda _: True, 8, name='allmatch'),
-        GroupWorkerLimit(lambda x: x.owner, 4),
-        GroupWorkerLimit(lambda x: x.sandbox, 2, name='sandbox'),
+        HashWorkerLimit(lambda x: x.owner, 4),
+        HashWorkerLimit(lambda x: x.sandbox, 2, name='sandbox'),
         ArchitectureWorkerLimit("x86_64", 3),
         ArchitectureWorkerLimit("aarch64", 2),
+        ArchitectureUserWorkerLimit("aarch64", 2),
         BuildTagLimit("special_requirement", 1),
     ]
     tasks = [BuildQueueTask(t) for t in TASKS]
@@ -126,10 +131,11 @@ def test_worker_limit_info():
         'w:7-fedora-rawhide-x86_64, w:7-fedora-32-x86_64, w:7-fedora-31-x86_64',
         "limit info: 'allmatch', matching: w:7, w:7-fedora-rawhide-x86_64, "
         'w:7-fedora-32-x86_64, w:7-fedora-31-x86_64',
-        "limit info: Unnamed 'GroupWorkerLimit' limit, counter: cecil=2, bedrich=2",
+        "limit info: Unnamed 'HashWorkerLimit' limit, counter: cecil=2, bedrich=2",
         "limit info: 'sandbox', counter: sb1=1, sb2=2",
-        "limit info: 'arch_x86_64'",
+        "limit info: 'arch_x86_64', matching: w:7-fedora-rawhide-x86_64, w:7-fedora-32-x86_64, w:7-fedora-31-x86_64",
         "limit info: 'arch_aarch64'",
+        "limit info: 'arch_aarch64_owner', counter: None_cecil=1, x86_64_cecil=1, x86_64_bedrich=2",
         "limit info: 'tag_special_requirement', matching: w:7-fedora-31-x86_64",
     ]
 
diff --git a/common/copr_common/worker_manager.py b/common/copr_common/worker_manager.py
index 8b5b8433b..5c53407f8 100644
--- a/common/copr_common/worker_manager.py
+++ b/common/copr_common/worker_manager.py
@@ -127,9 +127,10 @@ def __str__(self):
         return ", ".join(items)
 
 
-class GroupWorkerLimit(WorkerLimit):
+class HashWorkerLimit(WorkerLimit):
     """
-    Assign task to groups, and set maximum number of workers per each group.
+    Assign tasks to groups per the return value of the HASHER(TASK) method.  Set
+    maximum number of workers **per each such group**.
     """
     def __init__(self, hasher, limit, name=None):
         """
diff --git a/common/python-copr-common.spec b/common/python-copr-common.spec
index 64f7a3e0a..e48e61e72 100644
--- a/common/python-copr-common.spec
+++ b/common/python-copr-common.spec
@@ -16,7 +16,7 @@
 %endif
 
 Name:       python-copr-common
-Version:    0.20
+Version:    0.20.1.dev1
 Release:    1%{?dist}
 Summary:    Python code used by Copr
 
diff --git a/common/setup.py b/common/setup.py
index 605e778c1..083393aab 100644
--- a/common/setup.py
+++ b/common/setup.py
@@ -20,7 +20,7 @@
 
 setup(
     name='copr-common',
-    version="0.20",
+    version="0.20.1.dev1",
     description=__description__,
     long_description=long_description,
     author=__author__,
diff --git a/dist-git/copr-dist-git.spec b/dist-git/copr-dist-git.spec
index 39d799536..2e0293224 100644
--- a/dist-git/copr-dist-git.spec
+++ b/dist-git/copr-dist-git.spec
@@ -1,4 +1,4 @@
-%global copr_common_version 0.16.4.dev
+%global copr_common_version 0.20.1.dev1
 
 Name:       copr-dist-git
 Version:    0.67
diff --git a/dist-git/copr_dist_git/import_dispatcher.py b/dist-git/copr_dist_git/import_dispatcher.py
index bd31cb588..588001aed 100644
--- a/dist-git/copr_dist_git/import_dispatcher.py
+++ b/dist-git/copr_dist_git/import_dispatcher.py
@@ -6,7 +6,7 @@
 import sys
 import logging
 from copr_common.dispatcher import Dispatcher
-from copr_common.worker_manager import GroupWorkerLimit
+from copr_common.worker_manager import HashWorkerLimit
 from copr_dist_git.importer import Importer, ImportWorkerManager
 
 
@@ -48,7 +48,7 @@ def __init__(self, opts):
         for limit_type in ['sandbox', 'owner']:
             limit = LIMITS[limit_type]
             self.log.info("setting %s limit to %s", limit_type, limit)
-            self.limits.append(GroupWorkerLimit(
+            self.limits.append(HashWorkerLimit(
                 lambda x, limit=limit_type: getattr(x, limit),
                 limit,
                 name=limit_type,