diff --git a/server/schedule/filter/filters.go b/server/schedule/filter/filters.go
index bbc532aa365..0aeec5b79d4 100644
--- a/server/schedule/filter/filters.go
+++ b/server/schedule/filter/filters.go
@@ -16,6 +16,7 @@ package filter
 import (
 	"fmt"
 
+	"github.com/pingcap/kvproto/pkg/metapb"
 	"github.com/pingcap/log"
 	"github.com/tikv/pd/pkg/slice"
 	"github.com/tikv/pd/server/core"
@@ -540,7 +541,9 @@ func (f *ruleFitFilter) Source(opt opt.Options, store *core.StoreInfo) bool {
 }
 
 func (f *ruleFitFilter) Target(opt opt.Options, store *core.StoreInfo) bool {
-	region := f.region.Clone(core.WithReplacePeerStore(f.oldStore, store.GetID()))
+	region := createRegionForRuleFit(f.region.GetStartKey(), f.region.GetEndKey(),
+		f.region.GetPeers(), f.region.GetLeader(),
+		core.WithReplacePeerStore(f.oldStore, store.GetID()))
 	newFit := f.fitter.FitRegion(region)
 	return placement.CompareRegionFit(f.oldFit, newFit) <= 0
 }
@@ -583,8 +586,10 @@ func (f *ruleLeaderFitFilter) Target(opt opt.Options, store *core.StoreInfo) boo
 		log.Warn("ruleLeaderFitFilter couldn't find peer on target Store", zap.Uint64("target-store", store.GetID()))
 		return false
 	}
-	region := f.region.Clone(core.WithLeader(targetPeer))
-	newFit := f.fitter.FitRegion(region)
+	copyRegion := createRegionForRuleFit(f.region.GetStartKey(), f.region.GetEndKey(),
+		f.region.GetPeers(), f.region.GetLeader(),
+		core.WithLeader(targetPeer))
+	newFit := f.fitter.FitRegion(copyRegion)
 	return placement.CompareRegionFit(f.oldFit, newFit) <= 0
 }
 
@@ -712,3 +717,98 @@ const (
 
 var allSpecialUses = []string{SpecialUseHotRegion, SpecialUseReserved}
 var allSpeicalEngines = []string{EngineTiFlash}
+<<<<<<< HEAD
+=======
+
+type isolationFilter struct {
+	scope          string
+	locationLabels []string
+	constraintSet  [][]string
+}
+
+// NewIsolationFilter creates a filter that filters out stores with isolationLevel
+// For example, a region has 3 replicas in z1, z2 and z3 individually.
+// With isolationLevel = zone, if the region on z1 is down, we need to filter out z2 and z3
+// because these two zones already have one of the region's replicas on them.
+// We need to choose a store on z1 or z4 to place the new replica to meet the isolationLevel explicitly and forcibly.
+func NewIsolationFilter(scope, isolationLevel string, locationLabels []string, regionStores []*core.StoreInfo) Filter {
+	isolationFilter := &isolationFilter{
+		scope:          scope,
+		locationLabels: locationLabels,
+		constraintSet:  make([][]string, 0),
+	}
+	// Get which idx this isolationLevel at according to locationLabels
+	var isolationLevelIdx int
+	for level, label := range locationLabels {
+		if label == isolationLevel {
+			isolationLevelIdx = level
+			break
+		}
+	}
+	// Collect all constraints for given isolationLevel
+	for _, regionStore := range regionStores {
+		constraintList := make([]string, 0)
+		for i := 0; i <= isolationLevelIdx; i++ {
+			constraintList = append(constraintList, regionStore.GetLabelValue(locationLabels[i]))
+		}
+		isolationFilter.constraintSet = append(isolationFilter.constraintSet, constraintList)
+	}
+	return isolationFilter
+}
+
+func (f *isolationFilter) Scope() string {
+	return f.scope
+}
+
+func (f *isolationFilter) Type() string {
+	return "isolation-filter"
+}
+
+func (f *isolationFilter) Source(opt opt.Options, store *core.StoreInfo) bool {
+	return true
+}
+
+func (f *isolationFilter) Target(opt opt.Options, store *core.StoreInfo) bool {
+	// No isolation constraint to fit
+	if len(f.constraintSet) <= 0 {
+		return true
+	}
+	for _, constrainList := range f.constraintSet {
+		match := true
+		for idx, constraint := range constrainList {
+			// Check every constraint in constrainList
+			match = store.GetLabelValue(f.locationLabels[idx]) == constraint && match
+		}
+		if len(constrainList) > 0 && match {
+			return false
+		}
+	}
+	return true
+}
+
+// createRegionForRuleFit is used to create a clone region with RegionCreateOptions which is only used for
+// FitRegion in filter
+func createRegionForRuleFit(startKey, endKey []byte,
+	peers []*metapb.Peer, leader *metapb.Peer, opts ...core.RegionCreateOption) *core.RegionInfo {
+	copyLeader := &metapb.Peer{
+		Id:      leader.Id,
+		StoreId: leader.StoreId,
+		Role:    leader.Role,
+	}
+	copyPeers := make([]*metapb.Peer, 0, len(peers))
+	for _, p := range peers {
+		peer := &metapb.Peer{
+			Id:      p.Id,
+			StoreId: p.StoreId,
+			Role:    p.Role,
+		}
+		copyPeers = append(copyPeers, peer)
+	}
+	cloneRegion := core.NewRegionInfo(&metapb.Region{
+		StartKey: startKey,
+		EndKey:   endKey,
+		Peers:    copyPeers,
+	}, copyLeader, opts...)
+	return cloneRegion
+}
+>>>>>>> a0eba9b... filter: replace region.Clone in filter (#2794)
diff --git a/server/schedule/filter/filters_test.go b/server/schedule/filter/filters_test.go
index 9a35635ac88..716efccefd4 100644
--- a/server/schedule/filter/filters_test.go
+++ b/server/schedule/filter/filters_test.go
@@ -80,3 +80,28 @@ func (s *testFiltersSuite) TestRuleFitFilter(c *C) {
 	c.Assert(filter.Target(tc, tc.GetStore(4)), IsFalse)
 	c.Assert(filter.Source(tc, tc.GetStore(4)), IsTrue)
 }
+
+func BenchmarkCloneRegionTest(b *testing.B) {
+	epoch := &metapb.RegionEpoch{
+		ConfVer: 1,
+		Version: 1,
+	}
+	region := core.NewRegionInfo(
+		&metapb.Region{
+			Id:       4,
+			StartKey: []byte("x"),
+			EndKey:   []byte(""),
+			Peers: []*metapb.Peer{
+				{Id: 108, StoreId: 4},
+			},
+			RegionEpoch: epoch,
+		},
+		&metapb.Peer{Id: 108, StoreId: 4},
+		core.SetApproximateSize(50),
+		core.SetApproximateKeys(20),
+	)
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		_ = createRegionForRuleFit(region.GetStartKey(), region.GetEndKey(), region.GetPeers(), region.GetLeader())
+	}
+}