diff --git a/Makefile.util.mk b/Makefile.util.mk
index 18f6b0ff4986a95d140eee277761f292b7913c7c..98e2158effa20af4a14d0f5eb1af49eee5a1204c 100644
--- a/Makefile.util.mk
+++ b/Makefile.util.mk
@@ -17,6 +17,9 @@ complexity: .GOPATH/.ok bin/gocyclo
 test: .GOPATH/.ok gitlab-pages
 	go test $(if $V,-v) -timeout=1m $(allpackages)
 
+bench: .GOPATH/.ok gitlab-pages
+	go test -bench=. $(allpackages)
+
 # The acceptance tests cannot count for coverage
 cover: bin/gocovmerge .GOPATH/.ok
 	@echo "NOTE: make cover does not exit 1 on failure, don't use it to check for tests success!"
diff --git a/domain_config.go b/domain_config.go
index e0f00cc49869fd37dbd44ebccefde96a8fa8fb42..08601f669460a5cc6307edeaf8bf26db484f9dc3 100644
--- a/domain_config.go
+++ b/domain_config.go
@@ -29,7 +29,7 @@ func (c *domainConfig) Valid(rootDomain string) bool {
 }
 
 func (c *domainsConfig) Read(group, project string) (err error) {
-	configFile, err := os.Open(filepath.Join(group, project, "config.json"))
+	configFile, err := os.Open(filepath.Join(domainRoot, group, project, "config.json"))
 	if err != nil {
 		return err
 	}
diff --git a/domains.go b/domains.go
index 000aa42e9ef01d51541b68ec28844d0dadfefe6d..5ec27e3c0490f4ad572db11c7bf1cd775bb97bb3 100644
--- a/domains.go
+++ b/domains.go
@@ -62,7 +62,7 @@ func (d domains) readProject(rootDomain, group, project string) error {
 		return errors.New("deleted project")
 	}
 
-	_, err := os.Lstat(filepath.Join(group, project, "public"))
+	_, err := os.Lstat(filepath.Join(domainRoot, group, project, "public"))
 	if err != nil {
 		return errors.New("missing public/ in project")
 	}
@@ -72,7 +72,7 @@ func (d domains) readProject(rootDomain, group, project string) error {
 }
 
 func (d domains) readProjects(rootDomain, group string) (count int) {
-	projects, err := os.Open(group)
+	projects, err := os.Open(filepath.Join(domainRoot, group))
 	if err != nil {
 		return
 	}
@@ -97,8 +97,10 @@ func (d domains) readProjects(rootDomain, group string) (count int) {
 	return
 }
 
+var domainRoot = "."
+
 func (d domains) ReadGroups(rootDomain string) error {
-	groups, err := os.Open(".")
+	groups, err := os.Open(domainRoot)
 	if err != nil {
 		return err
 	}
diff --git a/domains_test.go b/domains_test.go
index 51bafc9f8426800ee6b00bf82f9b89d66e1332ae..9cd3f97eccd6db21f3ff191c131839ab82539245 100644
--- a/domains_test.go
+++ b/domains_test.go
@@ -2,6 +2,7 @@ package main
 
 import (
 	"crypto/rand"
+	"fmt"
 	"io/ioutil"
 	"os"
 	"testing"
@@ -81,3 +82,34 @@ func TestWatchDomains(t *testing.T) {
 	domains = <-update
 	assert.NotNil(t, domains, "if the domains are updated after the timestamp removal")
 }
+
+func BenchmarkReadGroups(b *testing.B) {
+	testRoot, err := ioutil.TempDir("", "gitlab-pages-test")
+	require.NoError(b, err)
+	defer os.RemoveAll(testRoot)
+
+	defer func(d string) {
+		domainRoot = d
+	}(domainRoot)
+	domainRoot = testRoot
+
+	nGroups := 10000
+	b.Logf("creating fake domains directory with %d groups", nGroups)
+	fakeConfig := []byte(`{"Domains":[{"Domain":"foo","Certificate":"bar","Key":"baz"}]}`)
+	for i := 0; i < nGroups; i++ {
+		for j := 0; j < 5; j++ {
+			dir := fmt.Sprintf("%s/group-%d/project-%d/public", testRoot, i, j)
+			require.NoError(b, os.MkdirAll(dir, 0755))
+			require.NoError(b, ioutil.WriteFile(dir+"/config.json", fakeConfig, 0644))
+		}
+		if i%100 == 0 {
+			fmt.Print(".")
+		}
+	}
+
+	b.Run("ReadGroups", func(b *testing.B) {
+		testDomains := domains(make(map[string]*domain))
+		require.NoError(b, testDomains.ReadGroups("example.com"))
+		b.Logf("found %d domains", len(testDomains))
+	})
+}