diff --git a/src/Coordination/Changelog.cpp b/src/Coordination/Changelog.cpp
index e4d8b13ec37..4f095974836 100644
--- a/src/Coordination/Changelog.cpp
+++ b/src/Coordination/Changelog.cpp
@@ -212,6 +212,8 @@ Changelog::Changelog(const std::string & changelogs_dir_, size_t rotate_interval
 void Changelog::readChangelogAndInitWriter(size_t from_log_idx)
 {
     size_t read_from_last = 0;
+    start_index = from_log_idx == 0 ? 1 : from_log_idx;
+    size_t total_read = 0;
     for (const auto & [start_id, changelog_file] : existing_changelogs)
     {
         ChangelogName parsed_name = getChangelogName(changelog_file);
@@ -219,11 +221,10 @@ void Changelog::readChangelogAndInitWriter(size_t from_log_idx)
         {
             ChangelogReader reader(changelog_file);
             read_from_last = reader.readChangelog(logs, from_log_idx, index_to_start_pos);
+            total_read += read_from_last;
         }
     }
 
-    start_index = from_log_idx == 0 ? 1 : from_log_idx;
-
     if (existing_changelogs.size() > 0 && read_from_last < rotate_interval)
     {
         auto str_name = existing_changelogs.rbegin()->second;
@@ -233,7 +234,7 @@ void Changelog::readChangelogAndInitWriter(size_t from_log_idx)
     }
     else
     {
-        rotate(start_index);
+        rotate(start_index + total_read);
     }
 }
 
diff --git a/src/Coordination/NuKeeperLogStore.cpp b/src/Coordination/NuKeeperLogStore.cpp
index fa0631e14ad..fa8d6d6c299 100644
--- a/src/Coordination/NuKeeperLogStore.cpp
+++ b/src/Coordination/NuKeeperLogStore.cpp
@@ -94,4 +94,10 @@ void NuKeeperLogStore::apply_pack(size_t index, nuraft::buffer & pack)
     changelog.applyEntriesFromBuffer(index, pack);
 }
 
+size_t NuKeeperLogStore::size() const
+{
+    std::lock_guard lock(changelog_lock);
+    return changelog.size();
+}
+
 }
diff --git a/src/Coordination/NuKeeperLogStore.h b/src/Coordination/NuKeeperLogStore.h
index 981dc3f24e7..49d5dbfdf7c 100644
--- a/src/Coordination/NuKeeperLogStore.h
+++ b/src/Coordination/NuKeeperLogStore.h
@@ -39,6 +39,8 @@ public:
 
     bool flush() override;
 
+    size_t size() const;
+
 private:
     mutable std::mutex changelog_lock;
     Changelog changelog;
diff --git a/src/Coordination/tests/gtest_for_build.cpp b/src/Coordination/tests/gtest_for_build.cpp
index 6d91ba95111..8328d93d9cf 100644
--- a/src/Coordination/tests/gtest_for_build.cpp
+++ b/src/Coordination/tests/gtest_for_build.cpp
@@ -114,10 +114,10 @@ struct SimpliestRaftServer
 
         if (!raft_instance)
         {
-            std::cerr << "Failed to initialize launcher (see the message "
-                         "in the log file)." << std::endl;
+            std::cerr << "Failed to initialize launcher" << std::endl;
             exit(-1);
         }
+
         std::cout << "init Raft instance " << server_id;
         for (size_t ii = 0; ii < 20; ++ii)
         {
@@ -370,33 +370,33 @@ DB::LogEntryPtr getLogEntry(const std::string & s, size_t term)
 TEST(CoordinationTest, ChangelogTestSimple)
 {
     ChangelogDirTest test("./logs");
-    DB::Changelog changelog("./logs", 5);
-    changelog.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog("./logs", 5);
+    changelog.init(1);
     auto entry = getLogEntry("hello world", 77);
-    changelog.appendEntry(1, entry);
-    EXPECT_EQ(changelog.getNextEntryIndex(), 2);
-    EXPECT_EQ(changelog.getStartIndex(), 1);
-    EXPECT_EQ(changelog.getLastEntry()->get_term(), 77);
-    EXPECT_EQ(changelog.entryAt(1)->get_term(), 77);
-    EXPECT_EQ(changelog.getLogEntriesBetween(1, 2)->size(), 1);
+    changelog.append(entry);
+    EXPECT_EQ(changelog.next_slot(), 2);
+    EXPECT_EQ(changelog.start_index(), 1);
+    EXPECT_EQ(changelog.last_entry()->get_term(), 77);
+    EXPECT_EQ(changelog.entry_at(1)->get_term(), 77);
+    EXPECT_EQ(changelog.log_entries(1, 2)->size(), 1);
 }
 
 TEST(CoordinationTest, ChangelogTestFile)
 {
     ChangelogDirTest test("./logs");
-    DB::Changelog changelog("./logs", 5);
-    changelog.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog("./logs", 5);
+    changelog.init(1);
     auto entry = getLogEntry("hello world", 77);
-    changelog.appendEntry(1, entry);
+    changelog.append(entry);
     EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
     for (const auto & p : fs::directory_iterator("./logs"))
         EXPECT_EQ(p.path(), "./logs/changelog_1_5.bin");
 
-    changelog.appendEntry(2, entry);
-    changelog.appendEntry(3, entry);
-    changelog.appendEntry(4, entry);
-    changelog.appendEntry(5, entry);
-    changelog.appendEntry(6, entry);
+    changelog.append(entry);
+    changelog.append(entry);
+    changelog.append(entry);
+    changelog.append(entry);
+    changelog.append(entry);
 
     EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
     EXPECT_TRUE(fs::exists("./logs/changelog_6_10.bin"));
@@ -405,26 +405,26 @@ TEST(CoordinationTest, ChangelogTestFile)
 TEST(CoordinationTest, ChangelogReadWrite)
 {
     ChangelogDirTest test("./logs");
-    DB::Changelog changelog("./logs", 1000);
-    changelog.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog("./logs", 1000);
+    changelog.init(1);
     for (size_t i = 0; i < 10; ++i)
     {
         auto entry = getLogEntry("hello world", i * 10);
-        changelog.appendEntry(changelog.getNextEntryIndex(), entry);
+        changelog.append(entry);
     }
     EXPECT_EQ(changelog.size(), 10);
-    DB::Changelog changelog_reader("./logs", 1000);
-    changelog_reader.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog_reader("./logs", 1000);
+    changelog_reader.init(1);
     EXPECT_EQ(changelog_reader.size(), 10);
-    EXPECT_EQ(changelog_reader.getLastEntry()->get_term(), changelog.getLastEntry()->get_term());
-    EXPECT_EQ(changelog_reader.getStartIndex(), changelog.getStartIndex());
-    EXPECT_EQ(changelog_reader.getNextEntryIndex(), changelog.getNextEntryIndex());
+    EXPECT_EQ(changelog_reader.last_entry()->get_term(), changelog.last_entry()->get_term());
+    EXPECT_EQ(changelog_reader.start_index(), changelog.start_index());
+    EXPECT_EQ(changelog_reader.next_slot(), changelog.next_slot());
 
     for (size_t i = 0; i < 10; ++i)
-        EXPECT_EQ(changelog_reader.entryAt(i + 1)->get_term(), changelog.entryAt(i + 1)->get_term());
+        EXPECT_EQ(changelog_reader.entry_at(i + 1)->get_term(), changelog.entry_at(i + 1)->get_term());
 
-    auto entries_from_range_read = changelog_reader.getLogEntriesBetween(1, 11);
-    auto entries_from_range = changelog.getLogEntriesBetween(1, 11);
+    auto entries_from_range_read = changelog_reader.log_entries(1, 11);
+    auto entries_from_range = changelog.log_entries(1, 11);
     EXPECT_EQ(entries_from_range_read->size(), entries_from_range->size());
     EXPECT_EQ(10, entries_from_range->size());
 }
@@ -432,55 +432,55 @@ TEST(CoordinationTest, ChangelogReadWrite)
 TEST(CoordinationTest, ChangelogWriteAt)
 {
     ChangelogDirTest test("./logs");
-    DB::Changelog changelog("./logs", 1000);
-    changelog.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog("./logs", 1000);
+    changelog.init(1);
     for (size_t i = 0; i < 10; ++i)
     {
         auto entry = getLogEntry("hello world", i * 10);
-        changelog.appendEntry(changelog.getNextEntryIndex(), entry);
+        changelog.append(entry);
     }
     EXPECT_EQ(changelog.size(), 10);
 
     auto entry = getLogEntry("writer", 77);
-    changelog.writeAt(7, entry);
+    changelog.write_at(7, entry);
     EXPECT_EQ(changelog.size(), 7);
-    EXPECT_EQ(changelog.getLastEntry()->get_term(), 77);
-    EXPECT_EQ(changelog.entryAt(7)->get_term(), 77);
-    EXPECT_EQ(changelog.getNextEntryIndex(), 8);
+    EXPECT_EQ(changelog.last_entry()->get_term(), 77);
+    EXPECT_EQ(changelog.entry_at(7)->get_term(), 77);
+    EXPECT_EQ(changelog.next_slot(), 8);
 
-    DB::Changelog changelog_reader("./logs", 1000);
-    changelog_reader.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog_reader("./logs", 1000);
+    changelog_reader.init(1);
 
     EXPECT_EQ(changelog_reader.size(), changelog.size());
-    EXPECT_EQ(changelog_reader.getLastEntry()->get_term(), changelog.getLastEntry()->get_term());
-    EXPECT_EQ(changelog_reader.getStartIndex(), changelog.getStartIndex());
-    EXPECT_EQ(changelog_reader.getNextEntryIndex(), changelog.getNextEntryIndex());
+    EXPECT_EQ(changelog_reader.last_entry()->get_term(), changelog.last_entry()->get_term());
+    EXPECT_EQ(changelog_reader.start_index(), changelog.start_index());
+    EXPECT_EQ(changelog_reader.next_slot(), changelog.next_slot());
 }
 
 
 TEST(CoordinationTest, ChangelogTestAppendAfterRead)
 {
     ChangelogDirTest test("./logs");
-    DB::Changelog changelog("./logs", 5);
-    changelog.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog("./logs", 5);
+    changelog.init(1);
     for (size_t i = 0; i < 7; ++i)
     {
         auto entry = getLogEntry("hello world", i * 10);
-        changelog.appendEntry(changelog.getNextEntryIndex(), entry);
+        changelog.append(entry);
     }
 
     EXPECT_EQ(changelog.size(), 7);
     EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
     EXPECT_TRUE(fs::exists("./logs/changelog_6_10.bin"));
 
-    DB::Changelog changelog_reader("./logs", 5);
-    changelog_reader.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog_reader("./logs", 5);
+    changelog_reader.init(1);
 
     EXPECT_EQ(changelog_reader.size(), 7);
     for (size_t i = 7; i < 10; ++i)
     {
         auto entry = getLogEntry("hello world", i * 10);
-        changelog_reader.appendEntry(changelog_reader.getNextEntryIndex(), entry);
+        changelog_reader.append(entry);
     }
     EXPECT_EQ(changelog_reader.size(), 10);
     EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
@@ -493,7 +493,7 @@ TEST(CoordinationTest, ChangelogTestAppendAfterRead)
     EXPECT_EQ(logs_count, 2);
 
     auto entry = getLogEntry("someentry", 77);
-    changelog_reader.appendEntry(changelog_reader.getNextEntryIndex(), entry);
+    changelog_reader.append(entry);
     EXPECT_EQ(changelog_reader.size(), 11);
     EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
     EXPECT_TRUE(fs::exists("./logs/changelog_6_10.bin"));
@@ -509,13 +509,13 @@ TEST(CoordinationTest, ChangelogTestAppendAfterRead)
 TEST(CoordinationTest, ChangelogTestCompaction)
 {
     ChangelogDirTest test("./logs");
-    DB::Changelog changelog("./logs", 5);
-    changelog.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog("./logs", 5);
+    changelog.init(1);
 
     for (size_t i = 0; i < 3; ++i)
     {
         auto entry = getLogEntry("hello world", i * 10);
-        changelog.appendEntry(changelog.getNextEntryIndex(), entry);
+        changelog.append(entry);
     }
 
     EXPECT_EQ(changelog.size(), 3);
@@ -523,15 +523,19 @@ TEST(CoordinationTest, ChangelogTestCompaction)
     changelog.compact(2);
 
     EXPECT_EQ(changelog.size(), 1);
-    EXPECT_EQ(changelog.getStartIndex(), 3);
-    EXPECT_EQ(changelog.getNextEntryIndex(), 4);
-    EXPECT_EQ(changelog.getLastEntry()->get_term(), 20);
+    EXPECT_EQ(changelog.start_index(), 3);
+    EXPECT_EQ(changelog.next_slot(), 4);
+    EXPECT_EQ(changelog.last_entry()->get_term(), 20);
     EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
 
-    changelog.appendEntry(changelog.getNextEntryIndex(), getLogEntry("hello world", 30));
-    changelog.appendEntry(changelog.getNextEntryIndex(), getLogEntry("hello world", 40));
-    changelog.appendEntry(changelog.getNextEntryIndex(), getLogEntry("hello world", 50));
-    changelog.appendEntry(changelog.getNextEntryIndex(), getLogEntry("hello world", 60));
+    auto e1 = getLogEntry("hello world", 30);
+    changelog.append(e1);
+    auto e2 = getLogEntry("hello world", 40);
+    changelog.append(e2);
+    auto e3 = getLogEntry("hello world", 50);
+    changelog.append(e3);
+    auto e4 = getLogEntry("hello world", 60);
+    changelog.append(e4);
 
     EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
     EXPECT_TRUE(fs::exists("./logs/changelog_6_10.bin"));
@@ -542,109 +546,110 @@ TEST(CoordinationTest, ChangelogTestCompaction)
     EXPECT_TRUE(fs::exists("./logs/changelog_6_10.bin"));
 
     EXPECT_EQ(changelog.size(), 1);
-    EXPECT_EQ(changelog.getStartIndex(), 7);
-    EXPECT_EQ(changelog.getNextEntryIndex(), 8);
-    EXPECT_EQ(changelog.getLastEntry()->get_term(), 60);
+    EXPECT_EQ(changelog.start_index(), 7);
+    EXPECT_EQ(changelog.next_slot(), 8);
+    EXPECT_EQ(changelog.last_entry()->get_term(), 60);
     /// And we able to read it
-    DB::Changelog changelog_reader("./logs", 5);
-    changelog_reader.readChangelogAndInitWriter(7);
+    DB::NuKeeperLogStore changelog_reader("./logs", 5);
+    changelog_reader.init(7);
     EXPECT_EQ(changelog_reader.size(), 1);
-    EXPECT_EQ(changelog_reader.getStartIndex(), 7);
-    EXPECT_EQ(changelog_reader.getNextEntryIndex(), 8);
-    EXPECT_EQ(changelog_reader.getLastEntry()->get_term(), 60);
+    EXPECT_EQ(changelog_reader.start_index(), 7);
+    EXPECT_EQ(changelog_reader.next_slot(), 8);
+    EXPECT_EQ(changelog_reader.last_entry()->get_term(), 60);
 }
 
 TEST(CoordinationTest, ChangelogTestBatchOperations)
 {
     ChangelogDirTest test("./logs");
-    DB::Changelog changelog("./logs", 100);
-    changelog.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog("./logs", 100);
+    changelog.init(1);
     for (size_t i = 0; i < 10; ++i)
     {
         auto entry = getLogEntry(std::to_string(i) + "_hello_world", i * 10);
-        changelog.appendEntry(changelog.getNextEntryIndex(), entry);
+        changelog.append(entry);
     }
 
     EXPECT_EQ(changelog.size(), 10);
 
-    auto entries = changelog.serializeEntriesToBuffer(1, 5);
+    auto entries = changelog.pack(1, 5);
 
-    DB::Changelog apply_changelog("./logs", 100);
-    apply_changelog.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore apply_changelog("./logs", 100);
+    apply_changelog.init(1);
 
     for (size_t i = 0; i < 10; ++i)
     {
-        EXPECT_EQ(apply_changelog.entryAt(i + 1)->get_term(), i * 10);
+        EXPECT_EQ(apply_changelog.entry_at(i + 1)->get_term(), i * 10);
     }
     EXPECT_EQ(apply_changelog.size(), 10);
 
-    apply_changelog.applyEntriesFromBuffer(8, *entries);
+    apply_changelog.apply_pack(8, *entries);
 
     EXPECT_EQ(apply_changelog.size(), 12);
-    EXPECT_EQ(apply_changelog.getStartIndex(), 1);
-    EXPECT_EQ(apply_changelog.getNextEntryIndex(), 13);
+    EXPECT_EQ(apply_changelog.start_index(), 1);
+    EXPECT_EQ(apply_changelog.next_slot(), 13);
 
     for (size_t i = 0; i < 7; ++i)
     {
-        EXPECT_EQ(apply_changelog.entryAt(i + 1)->get_term(), i * 10);
+        EXPECT_EQ(apply_changelog.entry_at(i + 1)->get_term(), i * 10);
     }
 
-    EXPECT_EQ(apply_changelog.entryAt(8)->get_term(), 0);
-    EXPECT_EQ(apply_changelog.entryAt(9)->get_term(), 10);
-    EXPECT_EQ(apply_changelog.entryAt(10)->get_term(), 20);
-    EXPECT_EQ(apply_changelog.entryAt(11)->get_term(), 30);
-    EXPECT_EQ(apply_changelog.entryAt(12)->get_term(), 40);
+    EXPECT_EQ(apply_changelog.entry_at(8)->get_term(), 0);
+    EXPECT_EQ(apply_changelog.entry_at(9)->get_term(), 10);
+    EXPECT_EQ(apply_changelog.entry_at(10)->get_term(), 20);
+    EXPECT_EQ(apply_changelog.entry_at(11)->get_term(), 30);
+    EXPECT_EQ(apply_changelog.entry_at(12)->get_term(), 40);
 }
 
 TEST(CoordinationTest, ChangelogTestBatchOperationsEmpty)
 {
     ChangelogDirTest test("./logs");
-    DB::Changelog changelog("./logs", 100);
-    changelog.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog("./logs", 100);
+    changelog.init(1);
     for (size_t i = 0; i < 10; ++i)
     {
         auto entry = getLogEntry(std::to_string(i) + "_hello_world", i * 10);
-        changelog.appendEntry(changelog.getNextEntryIndex(), entry);
+        changelog.append(entry);
     }
 
     EXPECT_EQ(changelog.size(), 10);
 
-    auto entries = changelog.serializeEntriesToBuffer(5, 5);
+    auto entries = changelog.pack(5, 5);
 
     ChangelogDirTest test1("./logs1");
-    DB::Changelog changelog_new("./logs1", 100);
-    changelog_new.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog_new("./logs1", 100);
+    changelog_new.init(1);
     EXPECT_EQ(changelog_new.size(), 0);
 
-    changelog_new.applyEntriesFromBuffer(5, *entries);
+    changelog_new.apply_pack(5, *entries);
 
     EXPECT_EQ(changelog_new.size(), 5);
-    EXPECT_EQ(changelog_new.getStartIndex(), 5);
-    EXPECT_EQ(changelog_new.getNextEntryIndex(), 10);
+    EXPECT_EQ(changelog_new.start_index(), 5);
+    EXPECT_EQ(changelog_new.next_slot(), 10);
 
     for (size_t i = 4; i < 9; ++i)
-        EXPECT_EQ(changelog_new.entryAt(i + 1)->get_term(), i * 10);
+        EXPECT_EQ(changelog_new.entry_at(i + 1)->get_term(), i * 10);
 
-    changelog_new.appendEntry(changelog_new.getNextEntryIndex(), getLogEntry("hello_world", 110));
+    auto e = getLogEntry("hello_world", 110);
+    changelog_new.append(e);
     EXPECT_EQ(changelog_new.size(), 6);
-    EXPECT_EQ(changelog_new.getStartIndex(), 5);
-    EXPECT_EQ(changelog_new.getNextEntryIndex(), 11);
+    EXPECT_EQ(changelog_new.start_index(), 5);
+    EXPECT_EQ(changelog_new.next_slot(), 11);
 
-    DB::Changelog changelog_reader("./logs1", 100);
-    changelog_reader.readChangelogAndInitWriter(5);
+    DB::NuKeeperLogStore changelog_reader("./logs1", 100);
+    changelog_reader.init(5);
 }
 
 
 TEST(CoordinationTest, ChangelogTestWriteAtPreviousFile)
 {
     ChangelogDirTest test("./logs");
-    DB::Changelog changelog("./logs", 5);
-    changelog.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog("./logs", 5);
+    changelog.init(1);
 
     for (size_t i = 0; i < 33; ++i)
     {
         auto entry = getLogEntry(std::to_string(i) + "_hello_world", i * 10);
-        changelog.appendEntry(changelog.getNextEntryIndex(), entry);
+        changelog.append(entry);
     }
 
     EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
@@ -657,11 +662,12 @@ TEST(CoordinationTest, ChangelogTestWriteAtPreviousFile)
 
     EXPECT_EQ(changelog.size(), 33);
 
-    changelog.writeAt(7, getLogEntry("helloworld", 5555));
+    auto e1 = getLogEntry("helloworld", 5555);
+    changelog.write_at(7, e1);
     EXPECT_EQ(changelog.size(), 7);
-    EXPECT_EQ(changelog.getStartIndex(), 1);
-    EXPECT_EQ(changelog.getNextEntryIndex(), 8);
-    EXPECT_EQ(changelog.getLastEntry()->get_term(), 5555);
+    EXPECT_EQ(changelog.start_index(), 1);
+    EXPECT_EQ(changelog.next_slot(), 8);
+    EXPECT_EQ(changelog.last_entry()->get_term(), 5555);
 
     EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
     EXPECT_TRUE(fs::exists("./logs/changelog_6_10.bin"));
@@ -672,24 +678,24 @@ TEST(CoordinationTest, ChangelogTestWriteAtPreviousFile)
     EXPECT_FALSE(fs::exists("./logs/changelog_26_30.bin"));
     EXPECT_FALSE(fs::exists("./logs/changelog_31_35.bin"));
 
-    DB::Changelog changelog_read("./logs", 5);
-    changelog_read.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog_read("./logs", 5);
+    changelog_read.init(1);
     EXPECT_EQ(changelog_read.size(), 7);
-    EXPECT_EQ(changelog_read.getStartIndex(), 1);
-    EXPECT_EQ(changelog_read.getNextEntryIndex(), 8);
-    EXPECT_EQ(changelog_read.getLastEntry()->get_term(), 5555);
+    EXPECT_EQ(changelog_read.start_index(), 1);
+    EXPECT_EQ(changelog_read.next_slot(), 8);
+    EXPECT_EQ(changelog_read.last_entry()->get_term(), 5555);
 }
 
 TEST(CoordinationTest, ChangelogTestWriteAtFileBorder)
 {
     ChangelogDirTest test("./logs");
-    DB::Changelog changelog("./logs", 5);
-    changelog.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog("./logs", 5);
+    changelog.init(1);
 
     for (size_t i = 0; i < 33; ++i)
     {
         auto entry = getLogEntry(std::to_string(i) + "_hello_world", i * 10);
-        changelog.appendEntry(changelog.getNextEntryIndex(), entry);
+        changelog.append(entry);
     }
 
     EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
@@ -702,11 +708,12 @@ TEST(CoordinationTest, ChangelogTestWriteAtFileBorder)
 
     EXPECT_EQ(changelog.size(), 33);
 
-    changelog.writeAt(11, getLogEntry("helloworld", 5555));
+    auto e1 = getLogEntry("helloworld", 5555);
+    changelog.write_at(11, e1);
     EXPECT_EQ(changelog.size(), 11);
-    EXPECT_EQ(changelog.getStartIndex(), 1);
-    EXPECT_EQ(changelog.getNextEntryIndex(), 12);
-    EXPECT_EQ(changelog.getLastEntry()->get_term(), 5555);
+    EXPECT_EQ(changelog.start_index(), 1);
+    EXPECT_EQ(changelog.next_slot(), 12);
+    EXPECT_EQ(changelog.last_entry()->get_term(), 5555);
 
     EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
     EXPECT_TRUE(fs::exists("./logs/changelog_6_10.bin"));
@@ -717,12 +724,90 @@ TEST(CoordinationTest, ChangelogTestWriteAtFileBorder)
     EXPECT_FALSE(fs::exists("./logs/changelog_26_30.bin"));
     EXPECT_FALSE(fs::exists("./logs/changelog_31_35.bin"));
 
-    DB::Changelog changelog_read("./logs", 5);
-    changelog_read.readChangelogAndInitWriter(1);
+    DB::NuKeeperLogStore changelog_read("./logs", 5);
+    changelog_read.init(1);
     EXPECT_EQ(changelog_read.size(), 11);
-    EXPECT_EQ(changelog_read.getStartIndex(), 1);
-    EXPECT_EQ(changelog_read.getNextEntryIndex(), 12);
-    EXPECT_EQ(changelog_read.getLastEntry()->get_term(), 5555);
+    EXPECT_EQ(changelog_read.start_index(), 1);
+    EXPECT_EQ(changelog_read.next_slot(), 12);
+    EXPECT_EQ(changelog_read.last_entry()->get_term(), 5555);
+}
+
+TEST(CoordinationTest, ChangelogTestWriteAtAllFiles)
+{
+    ChangelogDirTest test("./logs");
+    DB::NuKeeperLogStore changelog("./logs", 5);
+    changelog.init(1);
+
+    for (size_t i = 0; i < 33; ++i)
+    {
+        auto entry = getLogEntry(std::to_string(i) + "_hello_world", i * 10);
+        changelog.append(entry);
+    }
+
+    EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_6_10.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_11_15.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_16_20.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_21_25.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_26_30.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_31_35.bin"));
+
+    EXPECT_EQ(changelog.size(), 33);
+
+    auto e1 = getLogEntry("helloworld", 5555);
+    changelog.write_at(1, e1);
+    EXPECT_EQ(changelog.size(), 1);
+    EXPECT_EQ(changelog.start_index(), 1);
+    EXPECT_EQ(changelog.next_slot(), 2);
+    EXPECT_EQ(changelog.last_entry()->get_term(), 5555);
+
+    EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
+
+    EXPECT_FALSE(fs::exists("./logs/changelog_6_10.bin"));
+    EXPECT_FALSE(fs::exists("./logs/changelog_11_15.bin"));
+    EXPECT_FALSE(fs::exists("./logs/changelog_16_20.bin"));
+    EXPECT_FALSE(fs::exists("./logs/changelog_21_25.bin"));
+    EXPECT_FALSE(fs::exists("./logs/changelog_26_30.bin"));
+    EXPECT_FALSE(fs::exists("./logs/changelog_31_35.bin"));
+}
+
+TEST(CoordinationTest, ChangelogTestStartNewLogAfterRead)
+{
+    ChangelogDirTest test("./logs");
+    DB::NuKeeperLogStore changelog("./logs", 5);
+    changelog.init(1);
+
+    for (size_t i = 0; i < 35; ++i)
+    {
+        auto entry = getLogEntry(std::to_string(i) + "_hello_world", i * 10);
+        changelog.append(entry);
+    }
+    EXPECT_EQ(changelog.size(), 35);
+    EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_6_10.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_11_15.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_16_20.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_21_25.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_26_30.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_31_35.bin"));
+    EXPECT_FALSE(fs::exists("./logs/changelog_36_40.bin"));
+
+
+    DB::NuKeeperLogStore changelog_reader("./logs", 5);
+    changelog_reader.init(1);
+
+    auto entry = getLogEntry("36_hello_world", 360);
+    changelog_reader.append(entry);
+
+    EXPECT_EQ(changelog_reader.size(), 36);
+    EXPECT_TRUE(fs::exists("./logs/changelog_1_5.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_6_10.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_11_15.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_16_20.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_21_25.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_26_30.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_31_35.bin"));
+    EXPECT_TRUE(fs::exists("./logs/changelog_36_40.bin"));
 }
 
 #endif