diff --git a/crypto/vm/boc.cpp b/crypto/vm/boc.cpp
index c53595ff..8ff244d0 100644
--- a/crypto/vm/boc.cpp
+++ b/crypto/vm/boc.cpp
@@ -475,15 +475,128 @@ std::string BagOfCells::extract_string() const {
   return std::string{serialized.data(), serialized.data() + serialized.size()};
 }
 
-void BagOfCells::store_uint(unsigned long long value, unsigned bytes) {
-  unsigned char* ptr = store_ptr += bytes;
-  store_chk();
-  while (bytes) {
-    *--ptr = value & 0xff;
-    value >>= 8;
-    --bytes;
+namespace {
+struct BufferWriter {
+  BufferWriter(unsigned char* store_start, unsigned char* store_end)
+      : store_start(store_start), store_ptr(store_start), store_end(store_end) {}
+
+  size_t position() const {
+    return store_ptr - store_start;
   }
-  DCHECK(!bytes);
+  size_t remaining() const {
+    return store_end - store_ptr;
+  }
+  void chk() const {
+    DCHECK(store_ptr <= store_end);
+  }
+  bool empty() const {
+    return store_ptr == store_end;
+  }
+  void store_uint(unsigned long long value, unsigned bytes) {
+    unsigned char* ptr = store_ptr += bytes;
+    chk();
+    while (bytes) {
+      *--ptr = value & 0xff;
+      value >>= 8;
+      --bytes;
+    }
+    DCHECK(!bytes);
+  }
+  void store_bytes(unsigned char const* data, size_t s) {
+    store_ptr += s;
+    chk();
+    memcpy(store_ptr - s, data, s);
+  }
+  unsigned get_crc32() const {
+    return td::crc32c(td::Slice{store_start, store_ptr});
+  }
+
+ private:
+  unsigned char* store_start;
+  unsigned char* store_ptr;
+  unsigned char* store_end;
+};
+
+struct FileWriter {
+  FileWriter(td::FileFd& fd, size_t expected_size)
+      : fd(fd), expected_size(expected_size) {}
+
+  ~FileWriter() {
+    flush();
+  }
+
+  size_t position() const {
+    return flushed_size + writer.position();
+  }
+  size_t remaining() const {
+    return expected_size - position();
+  }
+  void chk() const {
+    DCHECK(position() <= expected_size);
+  }
+  bool empty() const {
+    return remaining() == 0;
+  }
+  void store_uint(unsigned long long value, unsigned bytes) {
+    flush_if_needed(bytes);
+    writer.store_uint(value, bytes);
+  }
+  void store_bytes(unsigned char const* data, size_t s) {
+    flush_if_needed(s);
+    writer.store_bytes(data, s);
+  }
+  unsigned get_crc32() const {
+    unsigned char const* start = buf.data();
+    unsigned char const* end = start + writer.position();
+    return td::crc32c_extend(current_crc32, td::Slice(start, end));
+  }
+
+  td::Status finalize() {
+    flush();
+    return std::move(res);
+  }
+
+ private:
+  void flush_if_needed(size_t s) {
+    DCHECK(s <= BUF_SIZE);
+    if (s > BUF_SIZE - writer.position()) {
+      flush();
+    }
+  }
+
+  void flush() {
+    chk();
+    unsigned char* start = buf.data();
+    unsigned char* end = start + writer.position();
+    if (start == end) {
+      return;
+    }
+    flushed_size += end - start;
+    current_crc32 = td::crc32c_extend(current_crc32, td::Slice(start, end));
+    if (res.is_ok()) {
+      while (end > start) {
+        auto R = fd.write(td::Slice(start, end));
+        if (R.is_error()) {
+          res = R.move_as_error();
+          break;
+        }
+        size_t s = R.move_as_ok();
+        start += s;
+      }
+    }
+    writer = BufferWriter(buf.data(), buf.data() + buf.size());
+  }
+
+  td::FileFd& fd;
+  size_t expected_size;
+  size_t flushed_size = 0;
+  unsigned current_crc32 = td::crc32c(td::Slice());
+
+  static const size_t BUF_SIZE = 1 << 22;
+  std::vector<unsigned char> buf = std::vector<unsigned char>(BUF_SIZE, '\0');
+  BufferWriter writer = BufferWriter(buf.data(), buf.data() + buf.size());
+  td::Status res = td::Status::OK();
+};
 }
 
 //serialized_boc#672fb0ac has_idx:(## 1) has_crc32c:(## 1)
@@ -497,13 +610,16 @@ void BagOfCells::store_uint(unsigned long long value, unsigned bytes) {
 //  index:(cells * ##(off_bytes * 8))
 //  cell_data:(tot_cells_size * [ uint8 ])
 //  = BagOfCells;
-std::size_t BagOfCells::serialize_to(unsigned char* buffer, std::size_t buff_size, int mode) {
-  std::size_t size_est = estimate_serialized_size(mode);
-  if (!size_est || size_est > buff_size) {
-    return 0;
-  }
-  init_store(buffer, buffer + size_est);
-  store_uint(info.magic, 4);
+template<typename WriterT>
+std::size_t BagOfCells::serialize_to_impl(WriterT& writer, int mode) {
+  auto store_ref = [&](unsigned long long value) {
+    writer.store_uint(value, info.ref_byte_size);
+  };
+  auto store_offset = [&](unsigned long long value) {
+    writer.store_uint(value, info.offset_byte_size);
+  };
+
+  writer.store_uint(info.magic, 4);
 
   td::uint8 byte{0};
   if (info.has_index) {
@@ -520,9 +636,9 @@ std::size_t BagOfCells::serialize_to(unsigned char* buffer, std::size_t buff_siz
     return 0;
   }
   byte |= static_cast<td::uint8>(info.ref_byte_size);
-  store_uint(byte, 1);
+  writer.store_uint(byte, 1);
 
-  store_uint(info.offset_byte_size, 1);
+  writer.store_uint(info.offset_byte_size, 1);
   store_ref(cell_count);
   store_ref(root_count);
   store_ref(0);
@@ -532,7 +648,7 @@ std::size_t BagOfCells::serialize_to(unsigned char* buffer, std::size_t buff_siz
     DCHECK(k >= 0 && k < cell_count);
     store_ref(k);
   }
-  DCHECK(store_ptr - buffer == (long long)info.index_offset);
+  DCHECK(writer.position() == info.index_offset);
   DCHECK((unsigned)cell_count == cell_list_.size());
   if (info.has_index) {
     std::size_t offs = 0;
@@ -551,8 +667,8 @@ std::size_t BagOfCells::serialize_to(unsigned char* buffer, std::size_t buff_siz
     }
     DCHECK(offs == info.data_size);
   }
-  DCHECK(store_ptr - buffer == (long long)info.data_offset);
-  unsigned char* keep_ptr = store_ptr;
+  DCHECK(writer.position() == info.data_offset);
+  size_t keep_position = writer.position();
   for (int i = 0; i < cell_count; ++i) {
     const auto& dc_info = cell_list_[cell_count - 1 - i];
     const Ref<DataCell>& dc = dc_info.dc_ref;
@@ -560,9 +676,9 @@ std::size_t BagOfCells::serialize_to(unsigned char* buffer, std::size_t buff_siz
     if (dc_info.is_root_cell && (mode & Mode::WithTopHash)) {
       with_hash = true;
     }
-    int s = dc->serialize(store_ptr, 256, with_hash);
-    store_ptr += s;
-    store_chk();
+    unsigned char buf[256];
+    int s = dc->serialize(buf, 256, with_hash);
+    writer.store_bytes(buf, s);
     DCHECK(dc->size_refs() == dc_info.ref_num);
     // std::cerr << (dc_info.is_special() ? '*' : ' ') << i << '<' << (int)dc_info.wt << ">:";
     for (unsigned j = 0; j < dc_info.ref_num; ++j) {
@@ -573,16 +689,38 @@ std::size_t BagOfCells::serialize_to(unsigned char* buffer, std::size_t buff_siz
     }
     // std::cerr << std::endl;
   }
-  store_chk();
-  DCHECK(store_ptr - keep_ptr == (long long)info.data_size);
-  DCHECK(store_end - store_ptr == (info.has_crc32c ? 4 : 0));
+  writer.chk();
+  DCHECK(writer.position() - keep_position == info.data_size);
+  DCHECK(writer.remaining() == (info.has_crc32c ? 4 : 0));
   if (info.has_crc32c) {
-    // compute crc32c of buffer .. store_ptr
-    unsigned crc = td::crc32c(td::Slice{buffer, store_ptr});
-    store_uint(td::bswap32(crc), 4);
+    unsigned crc = writer.get_crc32();
+    writer.store_uint(td::bswap32(crc), 4);
   }
-  DCHECK(store_empty());
-  return store_ptr - buffer;
+  DCHECK(writer.empty());
+  return writer.position();
+}
+
+std::size_t BagOfCells::serialize_to(unsigned char* buffer, std::size_t buff_size, int mode) {
+  std::size_t size_est = estimate_serialized_size(mode);
+  if (!size_est || size_est > buff_size) {
+    return 0;
+  }
+  BufferWriter writer{buffer, buffer + size_est};
+  return serialize_to_impl(writer, mode);
+}
+
+td::Status BagOfCells::serialize_to_file(td::FileFd& fd, int mode) {
+  std::size_t size_est = estimate_serialized_size(mode);
+  if (!size_est) {
+    return td::Status::Error("no cells to serialize to this bag of cells");
+  }
+  FileWriter writer{fd, size_est};
+  size_t s = serialize_to_impl(writer, mode);
+  TRY_STATUS(writer.finalize());
+  if (s != size_est) {
+    return td::Status::Error("error while serializing a bag of cells: actual serialized size differs from estimated");
+  }
+  return td::Status::OK();
 }
 
 unsigned long long BagOfCells::Info::read_int(const unsigned char* ptr, unsigned bytes) {
diff --git a/crypto/vm/boc.h b/crypto/vm/boc.h
index cc277a8c..02078e27 100644
--- a/crypto/vm/boc.h
+++ b/crypto/vm/boc.h
@@ -23,6 +23,7 @@
 #include "td/utils/buffer.h"
 #include "td/utils/HashMap.h"
 #include "td/utils/HashSet.h"
+#include "td/utils/port/FileFd.h"
 
 namespace vm {
 using td::Ref;
@@ -216,8 +217,6 @@ class BagOfCells {
   int max_depth{1024};
   Info info;
   unsigned long long data_bytes{0};
-  unsigned char* store_ptr{nullptr};
-  unsigned char* store_end{nullptr};
   td::HashMap<Hash, int> cells;
   struct CellInfo {
     Ref<DataCell> dc_ref;
@@ -267,6 +266,9 @@ class BagOfCells {
   std::string serialize_to_string(int mode = 0);
   td::Result<td::BufferSlice> serialize_to_slice(int mode = 0);
   std::size_t serialize_to(unsigned char* buffer, std::size_t buff_size, int mode = 0);
+  td::Status serialize_to_file(td::FileFd& fd, int mode = 0);
+  template<typename WriterT>
+  std::size_t serialize_to_impl(WriterT& writer, int mode = 0);
   std::string extract_string() const;
 
   td::Result<long long> deserialize(const td::Slice& data, int max_roots = default_max_roots);
@@ -295,23 +297,6 @@ class BagOfCells {
     cell_list_.clear();
   }
   td::uint64 compute_sizes(int mode, int& r_size, int& o_size);
-  void init_store(unsigned char* from, unsigned char* to) {
-    store_ptr = from;
-    store_end = to;
-  }
-  void store_chk() const {
-    DCHECK(store_ptr <= store_end);
-  }
-  bool store_empty() const {
-    return store_ptr == store_end;
-  }
-  void store_uint(unsigned long long value, unsigned bytes);
-  void store_ref(unsigned long long value) {
-    store_uint(value, info.ref_byte_size);
-  }
-  void store_offset(unsigned long long value) {
-    store_uint(value, info.offset_byte_size);
-  }
   void reorder_cells();
   int revisit(int cell_idx, int force = 0);
   unsigned long long get_idx_entry_raw(int index);
diff --git a/validator/db/archive-manager.cpp b/validator/db/archive-manager.cpp
index fb8f2c00..e7614154 100644
--- a/validator/db/archive-manager.cpp
+++ b/validator/db/archive-manager.cpp
@@ -336,6 +336,28 @@ void ArchiveManager::add_zero_state(BlockIdExt block_id, td::BufferSlice data, t
 
 void ArchiveManager::add_persistent_state(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::BufferSlice data,
                                           td::Promise<td::Unit> promise) {
+  auto create_writer = [&](std::string path, td::Promise<std::string> P) {
+    td::actor::create_actor<db::WriteFile>("writefile", db_root_ + "/archive/tmp/",
+                                           std::move(path), std::move(data), std::move(P))
+        .release();
+  };
+  add_persistent_state_impl(block_id, masterchain_block_id, std::move(promise), std::move(create_writer));
+}
+
+void ArchiveManager::add_persistent_state_gen(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                              std::function<td::Status(td::FileFd&)> write_state,
+                                              td::Promise<td::Unit> promise) {
+  auto create_writer = [&](std::string path, td::Promise<std::string> P) {
+    td::actor::create_actor<db::WriteFile>("writefile", db_root_ + "/archive/tmp/",
+                                           std::move(path), std::move(write_state), std::move(P))
+        .release();
+  };
+  add_persistent_state_impl(block_id, masterchain_block_id, std::move(promise), std::move(create_writer));
+}
+
+void ArchiveManager::add_persistent_state_impl(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                               td::Promise<td::Unit> promise,
+                                               std::function<void(std::string, td::Promise<std::string>)> create_writer) {
   auto id = FileReference{fileref::PersistentState{block_id, masterchain_block_id}};
   auto hash = id.hash();
   if (perm_states_.find(hash) != perm_states_.end()) {
@@ -353,8 +375,7 @@ void ArchiveManager::add_persistent_state(BlockIdExt block_id, BlockIdExt master
           promise.set_value(td::Unit());
         }
       });
-  td::actor::create_actor<db::WriteFile>("writefile", db_root_ + "/archive/tmp/", path, std::move(data), std::move(P))
-      .release();
+  create_writer(std::move(path), std::move(P));
 }
 
 void ArchiveManager::get_zero_state(BlockIdExt block_id, td::Promise<td::BufferSlice> promise) {
diff --git a/validator/db/archive-manager.hpp b/validator/db/archive-manager.hpp
index dbe6e4d4..31e0e6b6 100644
--- a/validator/db/archive-manager.hpp
+++ b/validator/db/archive-manager.hpp
@@ -45,6 +45,9 @@ class ArchiveManager : public td::actor::Actor {
   void add_zero_state(BlockIdExt block_id, td::BufferSlice data, td::Promise<td::Unit> promise);
   void add_persistent_state(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::BufferSlice data,
                             td::Promise<td::Unit> promise);
+  void add_persistent_state_gen(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                std::function<td::Status(td::FileFd&)> write_state,
+                                td::Promise<td::Unit> promise);
   void get_zero_state(BlockIdExt block_id, td::Promise<td::BufferSlice> promise);
   void get_persistent_state(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::Promise<td::BufferSlice> promise);
   void get_persistent_state_slice(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::int64 offset,
@@ -137,6 +140,8 @@ class ArchiveManager : public td::actor::Actor {
   PackageId get_max_temp_file_desc_idx();
   PackageId get_prev_temp_file_desc_idx(PackageId id);
 
+  void add_persistent_state_impl(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::Promise<td::Unit> promise,
+                                 std::function<void(std::string, td::Promise<std::string>)> create_writer);
   void written_perm_state(FileReferenceShort id);
 
   void persistent_state_gc(FileHash last);
diff --git a/validator/db/files-async.hpp b/validator/db/files-async.hpp
index 1f2ab5ce..2da534bf 100644
--- a/validator/db/files-async.hpp
+++ b/validator/db/files-async.hpp
@@ -52,30 +52,50 @@ class WriteFile : public td::actor::Actor {
     auto res = R.move_as_ok();
     auto file = std::move(res.first);
     auto old_name = res.second;
-    td::uint64 offset = 0;
-    while (data_.size() > 0) {
-      auto R = file.pwrite(data_.as_slice(), offset);
-      auto s = R.move_as_ok();
-      offset += s;
-      data_.confirm_read(s);
+    auto status = write_data_(file);
+    if (!status.is_error()) {
+      status = file.sync();
+    }
+    if (status.is_error()) {
+      td::unlink(old_name);
+      promise_.set_error(std::move(status));
+      stop();
+      return;
     }
-    file.sync().ensure();
     if (new_name_.length() > 0) {
-      td::rename(old_name, new_name_).ensure();
-      promise_.set_value(std::move(new_name_));
+      status = td::rename(old_name, new_name_);
+      if (status.is_error()) {
+        promise_.set_error(std::move(status));
+      } else {
+        promise_.set_value(std::move(new_name_));
+      }
     } else {
       promise_.set_value(std::move(old_name));
     }
     stop();
   }
+  WriteFile(std::string tmp_dir, std::string new_name, std::function<td::Status(td::FileFd&)> write_data,
+            td::Promise<std::string> promise)
+      : tmp_dir_(tmp_dir), new_name_(new_name), write_data_(std::move(write_data)), promise_(std::move(promise)) {
+  }
   WriteFile(std::string tmp_dir, std::string new_name, td::BufferSlice data, td::Promise<std::string> promise)
-      : tmp_dir_(tmp_dir), new_name_(new_name), data_(std::move(data)), promise_(std::move(promise)) {
+      : tmp_dir_(tmp_dir), new_name_(new_name), promise_(std::move(promise)) {
+    write_data_ = [data_ptr = std::make_shared<td::BufferSlice>(std::move(data))] (td::FileFd& fd) {
+      auto data = std::move(*data_ptr);
+      td::uint64 offset = 0;
+      while (data.size() > 0) {
+        TRY_RESULT(s, fd.pwrite(data.as_slice(), offset));
+        offset += s;
+        data.confirm_read(s);
+      }
+      return td::Status::OK();
+    };
   }
 
  private:
   const std::string tmp_dir_;
   std::string new_name_;
-  td::BufferSlice data_;
+  std::function<td::Status(td::FileFd&)> write_data_;
   td::Promise<std::string> promise_;
 };
 
diff --git a/validator/db/rootdb.cpp b/validator/db/rootdb.cpp
index ef88ad5f..58e3dd2f 100644
--- a/validator/db/rootdb.cpp
+++ b/validator/db/rootdb.cpp
@@ -276,6 +276,13 @@ void RootDb::store_persistent_state_file(BlockIdExt block_id, BlockIdExt masterc
                           std::move(state), std::move(promise));
 }
 
+void RootDb::store_persistent_state_file_gen(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                             std::function<td::Status(td::FileFd&)> write_data,
+                                             td::Promise<td::Unit> promise) {
+  td::actor::send_closure(archive_db_, &ArchiveManager::add_persistent_state_gen, block_id, masterchain_block_id,
+                          std::move(write_data), std::move(promise));
+}
+
 void RootDb::get_persistent_state_file(BlockIdExt block_id, BlockIdExt masterchain_block_id,
                                        td::Promise<td::BufferSlice> promise) {
   td::actor::send_closure(archive_db_, &ArchiveManager::get_persistent_state, block_id, masterchain_block_id,
diff --git a/validator/db/rootdb.hpp b/validator/db/rootdb.hpp
index c4d642e7..2654d482 100644
--- a/validator/db/rootdb.hpp
+++ b/validator/db/rootdb.hpp
@@ -69,6 +69,9 @@ class RootDb : public Db {
 
   void store_persistent_state_file(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::BufferSlice state,
                                    td::Promise<td::Unit> promise) override;
+  void store_persistent_state_file_gen(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                       std::function<td::Status(td::FileFd&)> write_data,
+                                       td::Promise<td::Unit> promise) override;
   void get_persistent_state_file(BlockIdExt block_id, BlockIdExt masterchain_block_id,
                                  td::Promise<td::BufferSlice> promise) override;
   void get_persistent_state_file_slice(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::int64 offset,
diff --git a/validator/impl/shard.cpp b/validator/impl/shard.cpp
index 18f71d32..a96f1a81 100644
--- a/validator/impl/shard.cpp
+++ b/validator/impl/shard.cpp
@@ -26,6 +26,7 @@
 #include "vm/cells/MerkleUpdate.h"
 #include "block/block-parse.h"
 #include "block/block-auto.h"
+#include "td/utils/filesystem.h"
 
 #define LAZY_STATE_DESERIALIZE 1
 
@@ -301,6 +302,30 @@ td::Result<td::BufferSlice> ShardStateQ::serialize() const {
   return st_res.move_as_ok();
 }
 
+td::Status ShardStateQ::serialize_to_file(td::FileFd& fd) const {
+  td::PerfWarningTimer perf_timer_{"serializestate", 0.1};
+  if (!data.is_null()) {
+    auto cur_data = data.clone();
+    while (cur_data.size() > 0) {
+      TRY_RESULT(s, fd.write(cur_data.as_slice()));
+      cur_data.confirm_read(s);
+    }
+    return td::Status::OK();
+  }
+  if (root.is_null()) {
+    return td::Status::Error(-666, "cannot serialize an uninitialized state");
+  }
+  vm::BagOfCells new_boc;
+  new_boc.set_root(root);
+  TRY_STATUS(new_boc.import_cells());
+  auto st_res = new_boc.serialize_to_file(fd, 31);
+  if (st_res.is_error()) {
+    LOG(ERROR) << "cannot serialize a shardchain state";
+    return st_res.move_as_error();
+  }
+  return td::Status::OK();
+}
+
 MasterchainStateQ::MasterchainStateQ(const BlockIdExt& _id, td::BufferSlice _data)
     : MasterchainState(), ShardStateQ(_id, std::move(_data)) {
 }
diff --git a/validator/impl/shard.hpp b/validator/impl/shard.hpp
index 862b0fc5..0056df11 100644
--- a/validator/impl/shard.hpp
+++ b/validator/impl/shard.hpp
@@ -87,6 +87,7 @@ class ShardStateQ : virtual public ShardState {
   td::Result<Ref<ShardState>> merge_with(const ShardState& with) const override;
   td::Result<std::pair<Ref<ShardState>, Ref<ShardState>>> split() const override;
   td::Result<td::BufferSlice> serialize() const override;
+  td::Status serialize_to_file(td::FileFd& fd) const override;
 };
 
 #if TD_MSVC
diff --git a/validator/interfaces/db.h b/validator/interfaces/db.h
index f49a7819..9983572b 100644
--- a/validator/interfaces/db.h
+++ b/validator/interfaces/db.h
@@ -53,6 +53,9 @@ class Db : public td::actor::Actor {
 
   virtual void store_persistent_state_file(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::BufferSlice state,
                                            td::Promise<td::Unit> promise) = 0;
+  virtual void store_persistent_state_file_gen(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                               std::function<td::Status(td::FileFd&)> write_data,
+                                               td::Promise<td::Unit> promise) = 0;
   virtual void get_persistent_state_file(BlockIdExt block_id, BlockIdExt masterchain_block_id,
                                          td::Promise<td::BufferSlice> promise) = 0;
   virtual void get_persistent_state_file_slice(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::int64 offset,
diff --git a/validator/interfaces/shard.h b/validator/interfaces/shard.h
index 0cfbda43..96ca8da2 100644
--- a/validator/interfaces/shard.h
+++ b/validator/interfaces/shard.h
@@ -55,6 +55,7 @@ class ShardState : public td::CntObject {
   virtual td::Result<std::pair<td::Ref<ShardState>, td::Ref<ShardState>>> split() const = 0;
 
   virtual td::Result<td::BufferSlice> serialize() const = 0;
+  virtual td::Status serialize_to_file(td::FileFd& fd) const = 0;
 };
 
 class MasterchainState : virtual public ShardState {
diff --git a/validator/interfaces/validator-manager.h b/validator/interfaces/validator-manager.h
index 1d4a7c9f..42e99ecc 100644
--- a/validator/interfaces/validator-manager.h
+++ b/validator/interfaces/validator-manager.h
@@ -57,6 +57,9 @@ class ValidatorManager : public ValidatorManagerInterface {
                                td::Promise<td::Ref<ShardState>> promise) = 0;
   virtual void store_persistent_state_file(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::BufferSlice state,
                                            td::Promise<td::Unit> promise) = 0;
+  virtual void store_persistent_state_file_gen(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                               std::function<td::Status(td::FileFd&)> write_data,
+                                               td::Promise<td::Unit> promise) = 0;
   virtual void store_zero_state_file(BlockIdExt block_id, td::BufferSlice state, td::Promise<td::Unit> promise) = 0;
   virtual void wait_block_state(BlockHandle handle, td::uint32 priority, td::Timestamp timeout,
                                 td::Promise<td::Ref<ShardState>> promise) = 0;
diff --git a/validator/manager-disk.cpp b/validator/manager-disk.cpp
index e43e37b2..404f7fe8 100644
--- a/validator/manager-disk.cpp
+++ b/validator/manager-disk.cpp
@@ -680,6 +680,13 @@ void ValidatorManagerImpl::store_persistent_state_file(BlockIdExt block_id, Bloc
                           std::move(promise));
 }
 
+void ValidatorManagerImpl::store_persistent_state_file_gen(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                                           std::function<td::Status(td::FileFd&)> write_data,
+                                                           td::Promise<td::Unit> promise) {
+  td::actor::send_closure(db_, &Db::store_persistent_state_file_gen, block_id, masterchain_block_id,
+                          std::move(write_data), std::move(promise));
+}
+
 void ValidatorManagerImpl::store_zero_state_file(BlockIdExt block_id, td::BufferSlice state,
                                                  td::Promise<td::Unit> promise) {
   td::actor::send_closure(db_, &Db::store_zero_state_file, block_id, std::move(state), std::move(promise));
diff --git a/validator/manager-disk.hpp b/validator/manager-disk.hpp
index fa365ccf..bb740b4c 100644
--- a/validator/manager-disk.hpp
+++ b/validator/manager-disk.hpp
@@ -143,6 +143,9 @@ class ValidatorManagerImpl : public ValidatorManager {
                        td::Promise<td::Ref<ShardState>> promise) override;
   void store_persistent_state_file(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::BufferSlice state,
                                    td::Promise<td::Unit> promise) override;
+  void store_persistent_state_file_gen(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                       std::function<td::Status(td::FileFd&)> write_data,
+                                       td::Promise<td::Unit> promise) override;
   void store_zero_state_file(BlockIdExt block_id, td::BufferSlice state, td::Promise<td::Unit> promise) override;
   void wait_block_state(BlockHandle handle, td::uint32 priority, td::Timestamp timeout,
                         td::Promise<td::Ref<ShardState>> promise) override;
diff --git a/validator/manager-hardfork.hpp b/validator/manager-hardfork.hpp
index 9938bcb2..71157dcc 100644
--- a/validator/manager-hardfork.hpp
+++ b/validator/manager-hardfork.hpp
@@ -169,6 +169,11 @@ class ValidatorManagerImpl : public ValidatorManager {
                                    td::Promise<td::Unit> promise) override {
     UNREACHABLE();
   }
+  void store_persistent_state_file_gen(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                       std::function<td::Status(td::FileFd&)> write_data,
+                                       td::Promise<td::Unit> promise) override {
+    UNREACHABLE();
+  }
   void store_zero_state_file(BlockIdExt block_id, td::BufferSlice state, td::Promise<td::Unit> promise) override {
     UNREACHABLE();
   }
diff --git a/validator/manager.cpp b/validator/manager.cpp
index e6fe5954..28e5cd3a 100644
--- a/validator/manager.cpp
+++ b/validator/manager.cpp
@@ -1051,6 +1051,13 @@ void ValidatorManagerImpl::store_persistent_state_file(BlockIdExt block_id, Bloc
                           std::move(promise));
 }
 
+void ValidatorManagerImpl::store_persistent_state_file_gen(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                                           std::function<td::Status(td::FileFd&)> write_data,
+                                                           td::Promise<td::Unit> promise) {
+  td::actor::send_closure(db_, &Db::store_persistent_state_file_gen, block_id, masterchain_block_id,
+                          std::move(write_data), std::move(promise));
+}
+
 void ValidatorManagerImpl::store_zero_state_file(BlockIdExt block_id, td::BufferSlice state,
                                                  td::Promise<td::Unit> promise) {
   td::actor::send_closure(db_, &Db::store_zero_state_file, block_id, std::move(state), std::move(promise));
diff --git a/validator/manager.hpp b/validator/manager.hpp
index 19ee4cdd..123625b2 100644
--- a/validator/manager.hpp
+++ b/validator/manager.hpp
@@ -347,6 +347,9 @@ class ValidatorManagerImpl : public ValidatorManager {
                        td::Promise<td::Ref<ShardState>> promise) override;
   void store_persistent_state_file(BlockIdExt block_id, BlockIdExt masterchain_block_id, td::BufferSlice state,
                                    td::Promise<td::Unit> promise) override;
+  void store_persistent_state_file_gen(BlockIdExt block_id, BlockIdExt masterchain_block_id,
+                                       std::function<td::Status(td::FileFd&)> write_data,
+                                       td::Promise<td::Unit> promise) override;
   void store_zero_state_file(BlockIdExt block_id, td::BufferSlice state, td::Promise<td::Unit> promise) override;
   void wait_block_state(BlockHandle handle, td::uint32 priority, td::Timestamp timeout,
                         td::Promise<td::Ref<ShardState>> promise) override;
diff --git a/validator/net/download-state.cpp b/validator/net/download-state.cpp
index 49986ce9..fedfaae8 100644
--- a/validator/net/download-state.cpp
+++ b/validator/net/download-state.cpp
@@ -149,6 +149,7 @@ void DownloadState::got_block_state_description(td::BufferSlice data) {
     abort_query(F.move_as_error());
     return;
   }
+  prev_logged_timer_ = td::Timer();
 
   ton_api::downcast_call(
       *F.move_as_ok().get(),
@@ -188,8 +189,12 @@ void DownloadState::got_block_state_part(td::BufferSlice data, td::uint32 reques
   sum_ += data.size();
   parts_.push_back(std::move(data));
 
-  if (sum_ % (1 << 22) == 0) {
-    LOG(DEBUG) << "downloading state " << block_id_ << ": total=" << sum_;
+  double elapsed = prev_logged_timer_.elapsed();
+  if (elapsed > 10.0) {
+    prev_logged_timer_ = td::Timer();
+    LOG(INFO) << "downloading state " << block_id_ << ": total=" << sum_ <<
+        " (" << double(sum_ - prev_logged_sum_) / elapsed << " B/s)";
+    prev_logged_sum_ = sum_;
   }
 
   if (last_part) {
diff --git a/validator/net/download-state.hpp b/validator/net/download-state.hpp
index d965e3c7..a586f61f 100644
--- a/validator/net/download-state.hpp
+++ b/validator/net/download-state.hpp
@@ -72,6 +72,9 @@ class DownloadState : public td::actor::Actor {
   td::BufferSlice state_;
   std::vector<td::BufferSlice> parts_;
   td::uint64 sum_ = 0;
+
+  td::uint64 prev_logged_sum_ = 0;
+  td::Timer prev_logged_timer_;
 };
 
 }  // namespace fullnode
diff --git a/validator/state-serializer.cpp b/validator/state-serializer.cpp
index 63b7b864..daf2de11 100644
--- a/validator/state-serializer.cpp
+++ b/validator/state-serializer.cpp
@@ -122,14 +122,12 @@ void AsyncStateSerializer::next_iteration() {
   CHECK(masterchain_handle_->id() == last_block_id_);
   if (attempt_ < max_attempt() && last_key_block_id_.id.seqno < last_block_id_.id.seqno &&
       need_serialize(masterchain_handle_)) {
-    if (masterchain_state_.is_null()) {
+    if (!have_masterchain_state_) {
           // block next attempts immediately, but send actual request later
           running_ = true;
           delay_action(
             [SelfId = actor_id(this)]() { td::actor::send_closure(SelfId, &AsyncStateSerializer::request_masterchain_state); },
-            // Masterchain is more important and much lighter than shards
-            // thus lower delay
-            td::Timestamp::in(td::Random::fast(0, 600)));
+            td::Timestamp::in(td::Random::fast(0, 3600)));
       return;
     }
     while (next_idx_ < shards_.size()) {
@@ -140,8 +138,6 @@ void AsyncStateSerializer::next_iteration() {
           running_ = true;
           delay_action(
             [SelfId = actor_id(this), shard = shards_[next_idx_]]() { td::actor::send_closure(SelfId, &AsyncStateSerializer::request_shard_state, shard); },
-            // Shards are less important and heavier than master
-            // thus higher delay
             td::Timestamp::in(td::Random::fast(0, 4 * 3600)));
         return;
       }
@@ -162,7 +158,7 @@ void AsyncStateSerializer::next_iteration() {
   }
   if (masterchain_handle_->inited_next_left()) {
     last_block_id_ = masterchain_handle_->one_next(true);
-    masterchain_state_ = td::Ref<MasterchainState>{};
+    have_masterchain_state_ = false;
     masterchain_handle_ = nullptr;
     saved_to_db_ = false;
     shards_.clear();
@@ -186,25 +182,25 @@ void AsyncStateSerializer::got_masterchain_handle(BlockHandle handle) {
 }
 
 void AsyncStateSerializer::got_masterchain_state(td::Ref<MasterchainState> state) {
-  masterchain_state_ = state;
+  have_masterchain_state_ = true;
   CHECK(next_idx_ == 0);
   CHECK(shards_.size() == 0);
 
-  auto vec = masterchain_state_->get_shards();
-  shards_.push_back(masterchain_handle_->id());
+  auto vec = state->get_shards();
   for (auto &v : vec) {
     shards_.push_back(v->top_block_id());
   }
 
-  auto B = masterchain_state_->serialize();
-  B.ensure();
+  auto write_data = [state] (td::FileFd& fd) {
+    return state->serialize_to_file(fd);
+  };
   auto P = td::PromiseCreator::lambda([SelfId = actor_id(this)](td::Result<td::Unit> R) {
     R.ensure();
     td::actor::send_closure(SelfId, &AsyncStateSerializer::stored_masterchain_state);
   });
 
-  td::actor::send_closure(manager_, &ValidatorManager::store_persistent_state_file, masterchain_handle_->id(),
-                          masterchain_handle_->id(), B.move_as_ok(), std::move(P));
+  td::actor::send_closure(manager_, &ValidatorManager::store_persistent_state_file_gen, masterchain_handle_->id(),
+                          masterchain_handle_->id(), write_data, std::move(P));
 }
 
 void AsyncStateSerializer::stored_masterchain_state() {
@@ -225,13 +221,15 @@ void AsyncStateSerializer::got_shard_handle(BlockHandle handle) {
 }
 
 void AsyncStateSerializer::got_shard_state(BlockHandle handle, td::Ref<ShardState> state) {
-  auto B = state->serialize().move_as_ok();
+  auto write_data = [state] (td::FileFd& fd) {
+    return state->serialize_to_file(fd);
+  };
   auto P = td::PromiseCreator::lambda([SelfId = actor_id(this)](td::Result<td::Unit> R) {
     R.ensure();
     td::actor::send_closure(SelfId, &AsyncStateSerializer::success_handler);
   });
-  td::actor::send_closure(manager_, &ValidatorManager::store_persistent_state_file, handle->id(),
-                          masterchain_handle_->id(), std::move(B), std::move(P));
+  td::actor::send_closure(manager_, &ValidatorManager::store_persistent_state_file_gen, handle->id(),
+                          masterchain_handle_->id(), write_data, std::move(P));
   LOG(INFO) << "storing persistent state for " << masterchain_handle_->id().seqno() << ":" << handle->id().id.shard;
   next_idx_++;
 }
diff --git a/validator/state-serializer.hpp b/validator/state-serializer.hpp
index 162e96c1..14261df7 100644
--- a/validator/state-serializer.hpp
+++ b/validator/state-serializer.hpp
@@ -43,7 +43,7 @@ class AsyncStateSerializer : public td::actor::Actor {
   td::uint32 next_idx_ = 0;
 
   BlockHandle masterchain_handle_;
-  td::Ref<MasterchainState> masterchain_state_;
+  bool have_masterchain_state_ = false;
 
   std::vector<BlockIdExt> shards_;
 
diff --git a/validator/validator.h b/validator/validator.h
index 349824d6..46110c92 100644
--- a/validator/validator.h
+++ b/validator/validator.h
@@ -96,7 +96,7 @@ struct ValidatorManagerOptions : public td::CntObject {
       BlockIdExt zero_block_id, BlockIdExt init_block_id,
       std::function<bool(ShardIdFull, CatchainSeqno, ShardCheckMode)> check_shard = [](ShardIdFull, CatchainSeqno,
                                                                                        ShardCheckMode) { return true; },
-      bool allow_blockchain_init = false, double sync_blocks_before = 300, double block_ttl = 86400 * 7,
+      bool allow_blockchain_init = false, double sync_blocks_before = 86400, double block_ttl = 86400 * 7,
       double state_ttl = 3600, double archive_ttl = 86400 * 365, double key_proof_ttl = 86400 * 3650,
       double max_mempool_num = 999999,
       bool initial_sync_disabled = false);