diff --git a/trunk/src/app/srs_app_config.cpp b/trunk/src/app/srs_app_config.cpp
index b5e1ca9d8..8ff779870 100644
--- a/trunk/src/app/srs_app_config.cpp
+++ b/trunk/src/app/srs_app_config.cpp
@@ -222,6 +222,14 @@ bool srs_directive_equals(SrsConfDirective* a, SrsConfDirective* b, string excep
     return true;
 }
 
+void set_config_directive(SrsConfDirective* parent, string dir, string value)
+{
+    SrsConfDirective* d = parent->get_or_create(dir);
+    d->name = dir;
+    d->args.clear();
+    d->args.push_back(value);
+}
+
 bool srs_config_hls_is_on_error_ignore(string strategy)
 {
     return strategy == "ignore";
@@ -864,6 +872,7 @@ srs_error_t SrsConfDirective::persistence(SrsFileWriter* writer, int level)
     return err;
 }
 
+// LCOV_EXCL_START
 SrsJsonArray* SrsConfDirective::dumps_args()
 {
     SrsJsonArray* arr = SrsJsonAny::array();
@@ -893,6 +902,7 @@ SrsJsonAny* SrsConfDirective::dumps_arg0_to_boolean()
 {
     return SrsJsonAny::boolean(arg0() == "on");
 }
+// LCOV_EXCL_STOP
 
 // see: ngx_conf_parse
 srs_error_t SrsConfDirective::parse_conf(SrsConfigBuffer* buffer, SrsDirectiveType type)
@@ -1122,24 +1132,6 @@ bool SrsConfig::is_dolphin()
     return dolphin;
 }
 
-void SrsConfig::set_config_directive(SrsConfDirective* parent, string dir, string value)
-{
-    SrsConfDirective* d = parent->get(dir);
-    
-    if (!d) {
-        d = new SrsConfDirective();
-        if (!dir.empty()) {
-            d->name = dir;
-        }
-        parent->directives.push_back(d);
-    }
-    
-    d->args.clear();
-    if (!value.empty()) {
-        d->args.push_back(value);
-    }
-}
-
 void SrsConfig::subscribe(ISrsReloadHandler* handler)
 {
     std::vector<ISrsReloadHandler*>::iterator it;
diff --git a/trunk/src/app/srs_app_config.hpp b/trunk/src/app/srs_app_config.hpp
index 602e5e22c..6bc0b4cf2 100644
--- a/trunk/src/app/srs_app_config.hpp
+++ b/trunk/src/app/srs_app_config.hpp
@@ -308,9 +308,7 @@ public:
 public:
     // Whether srs is in dolphin mode.
     virtual bool is_dolphin();
-private:
-    virtual void set_config_directive(SrsConfDirective* parent, std::string dir, std::string value);
-// Reload 
+// Reload
 public:
     // For reload handler to register itself,
     // when config service do the reload, callback the handler.
diff --git a/trunk/src/utest/srs_utest_config.cpp b/trunk/src/utest/srs_utest_config.cpp
index 864637380..b0211540b 100644
--- a/trunk/src/utest/srs_utest_config.cpp
+++ b/trunk/src/utest/srs_utest_config.cpp
@@ -32,6 +32,7 @@ using namespace std;
 #include <srs_kernel_utility.hpp>
 #include <srs_service_st.hpp>
 #include <srs_rtmp_stack.hpp>
+#include <srs_utest_kernel.hpp>
 
 MockSrsConfigBuffer::MockSrsConfigBuffer(string buf)
 {
@@ -2281,3 +2282,212 @@ VOID TEST(ConfigUnitTest, TransformForVhost)
     }
 }
 
+VOID TEST(ConfigUnitTest, DirectiveCopy)
+{
+    if (true) {
+        SrsConfDirective d;
+        d.name = "vhost";
+        d.get_or_create("enabled", "on");
+
+        SrsConfDirective* cp = d.copy();
+        ASSERT_TRUE(cp != NULL);
+        EXPECT_STREQ("vhost", cp->name.c_str());
+        ASSERT_TRUE(cp->get("enabled") != NULL);
+        EXPECT_STREQ("on", cp->get("enabled")->arg0().c_str());
+        srs_freep(cp);
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.name = "vhost";
+        d.get_or_create("enabled", "on");
+
+        SrsConfDirective* cp = d.copy("enabled");
+        ASSERT_TRUE(cp != NULL);
+        EXPECT_STREQ("vhost", cp->name.c_str());
+        ASSERT_TRUE(cp->get("enabled") == NULL);
+        srs_freep(cp);
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.name = "vhost";
+        d.get_or_create("enabled", "on");
+        d.get_or_create("hls");
+
+        SrsConfDirective* cp = d.copy("hls");
+        ASSERT_TRUE(cp != NULL);
+        EXPECT_STREQ("vhost", cp->name.c_str());
+        ASSERT_TRUE(cp->get("enabled") != NULL);
+        EXPECT_STREQ("on", cp->get("enabled")->arg0().c_str());
+        srs_freep(cp);
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        EXPECT_TRUE(d.arg0().empty());
+        EXPECT_TRUE(d.arg1().empty());
+        EXPECT_TRUE(d.arg2().empty());
+        EXPECT_TRUE(d.arg3().empty());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.args.push_back("a0");
+        EXPECT_STREQ("a0", d.arg0().c_str());
+        EXPECT_TRUE(d.arg1().empty());
+        EXPECT_TRUE(d.arg2().empty());
+        EXPECT_TRUE(d.arg3().empty());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.args.push_back("a0");
+        d.args.push_back("a1");
+        EXPECT_STREQ("a0", d.arg0().c_str());
+        EXPECT_STREQ("a1", d.arg1().c_str());
+        EXPECT_TRUE(d.arg2().empty());
+        EXPECT_TRUE(d.arg3().empty());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.args.push_back("a0");
+        d.args.push_back("a1");
+        d.args.push_back("a2");
+        EXPECT_STREQ("a0", d.arg0().c_str());
+        EXPECT_STREQ("a1", d.arg1().c_str());
+        EXPECT_STREQ("a2", d.arg2().c_str());
+        EXPECT_TRUE(d.arg3().empty());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.args.push_back("a0");
+        d.args.push_back("a1");
+        d.args.push_back("a2");
+        d.args.push_back("a3");
+        EXPECT_STREQ("a0", d.arg0().c_str());
+        EXPECT_STREQ("a1", d.arg1().c_str());
+        EXPECT_STREQ("a2", d.arg2().c_str());
+        EXPECT_STREQ("a3", d.arg3().c_str());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.set_arg0("a0");
+        EXPECT_STREQ("a0", d.arg0().c_str());
+        EXPECT_TRUE(d.arg1().empty());
+        EXPECT_TRUE(d.arg2().empty());
+        EXPECT_TRUE(d.arg3().empty());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.args.push_back("a0");
+        d.set_arg0("a0");
+        EXPECT_STREQ("a0", d.arg0().c_str());
+        EXPECT_TRUE(d.arg1().empty());
+        EXPECT_TRUE(d.arg2().empty());
+        EXPECT_TRUE(d.arg3().empty());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.args.push_back("a1");
+        d.set_arg0("a0");
+        EXPECT_STREQ("a0", d.arg0().c_str());
+        EXPECT_TRUE(d.arg1().empty());
+        EXPECT_TRUE(d.arg2().empty());
+        EXPECT_TRUE(d.arg3().empty());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+
+        SrsConfDirective* vhost = d.get_or_create("vhost");
+        d.remove(vhost);
+        srs_freep(vhost);
+
+        EXPECT_TRUE(d.get("vhost") == NULL);
+    }
+}
+
+extern void set_config_directive(SrsConfDirective* parent, string dir, string value);
+
+VOID TEST(ConfigUnitTest, PersistenceConfig)
+{
+    srs_error_t err;
+
+    if (true) {
+        SrsConfDirective d;
+        MockSrsFileWriter fw;
+        HELPER_ASSERT_SUCCESS(d.persistence(&fw, 0));
+        EXPECT_STREQ("", fw.str().c_str());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.name = "root";
+        d.args.push_back("on");
+
+        MockSrsFileWriter fw;
+        HELPER_ASSERT_SUCCESS(d.persistence(&fw, 0));
+        EXPECT_STREQ("", fw.str().c_str());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.get_or_create("global");
+
+        MockSrsFileWriter fw;
+        HELPER_ASSERT_SUCCESS(d.persistence(&fw, 0));
+        EXPECT_STREQ("global;\n", fw.str().c_str());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        d.get_or_create("global", "on");
+
+        MockSrsFileWriter fw;
+        HELPER_ASSERT_SUCCESS(d.persistence(&fw, 0));
+        EXPECT_STREQ("global on;\n", fw.str().c_str());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        SrsConfDirective* p = d.get_or_create("global", "on");
+        p->get_or_create("child", "100");
+        p->get_or_create("sibling", "101");
+
+        MockSrsFileWriter fw;
+        HELPER_ASSERT_SUCCESS(d.persistence(&fw, 0));
+        EXPECT_STREQ("global on {\n    child 100;\n    sibling 101;\n}\n", fw.str().c_str());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        SrsConfDirective* p = d.get_or_create("global", "on");
+        SrsConfDirective* pp = p->get_or_create("child", "100");
+        p->get_or_create("sibling", "101");
+        pp->get_or_create("grandson", "200");
+
+        MockSrsFileWriter fw;
+        HELPER_ASSERT_SUCCESS(d.persistence(&fw, 0));
+        EXPECT_STREQ("global on {\n    child 100 {\n        grandson 200;\n    }\n    sibling 101;\n}\n", fw.str().c_str());
+    }
+
+    if (true) {
+        SrsConfDirective d;
+        set_config_directive(&d, "vhost", "on");
+
+        ASSERT_TRUE(d.get("vhost") != NULL);
+        EXPECT_STREQ("on", d.get("vhost")->arg0().c_str());
+
+        set_config_directive(&d, "vhost", "off");
+
+        ASSERT_TRUE(d.get("vhost") != NULL);
+        EXPECT_STREQ("off", d.get("vhost")->arg0().c_str());
+    }
+}
+
diff --git a/trunk/src/utest/srs_utest_kernel.cpp b/trunk/src/utest/srs_utest_kernel.cpp
index e73914c13..8f62186cc 100644
--- a/trunk/src/utest/srs_utest_kernel.cpp
+++ b/trunk/src/utest/srs_utest_kernel.cpp
@@ -195,6 +195,16 @@ char* MockSrsFileWriter::data()
     return uf->_data.bytes();
 }
 
+string MockSrsFileWriter::str()
+{
+    int size = filesize();
+    if (size == 0) {
+        return "";
+    }
+
+    return string(data(), size);
+}
+
 srs_error_t MockSrsFileWriter::write(void* buf, size_t count, ssize_t* pnwrite)
 {
     if (err != srs_success) {
diff --git a/trunk/src/utest/srs_utest_kernel.hpp b/trunk/src/utest/srs_utest_kernel.hpp
index 6db2b7d35..90efb4ee9 100644
--- a/trunk/src/utest/srs_utest_kernel.hpp
+++ b/trunk/src/utest/srs_utest_kernel.hpp
@@ -74,6 +74,7 @@ public:
     virtual int64_t tellg();
     virtual int64_t filesize();
     virtual char* data();
+    virtual string str();
 public:
     virtual srs_error_t write(void* buf, size_t count, ssize_t* pnwrite);
     virtual srs_error_t lseek(off_t offset, int whence, off_t* seeked);