diff --git a/tddb/td/db/KeyValue.h b/tddb/td/db/KeyValue.h
index 4e0d85384..4f30a272b 100644
--- a/tddb/td/db/KeyValue.h
+++ b/tddb/td/db/KeyValue.h
@@ -19,6 +19,7 @@
 #pragma once
 #include "td/utils/Status.h"
 #include "td/utils/logging.h"
+#include <functional>
 namespace td {
 class KeyValueReader {
  public:
@@ -27,6 +28,9 @@ class KeyValueReader {
 
   virtual Result<GetStatus> get(Slice key, std::string &value) = 0;
   virtual Result<size_t> count(Slice prefix) = 0;
+  virtual Status for_each(std::function<Status(Slice, Slice)> f) {
+    return Status::Error("for_each is not supported");
+  }
 };
 
 class PrefixedKeyValueReader : public KeyValueReader {
diff --git a/tddb/td/db/RocksDb.cpp b/tddb/td/db/RocksDb.cpp
index 91c5ca662..f8688c006 100644
--- a/tddb/td/db/RocksDb.cpp
+++ b/tddb/td/db/RocksDb.cpp
@@ -56,7 +56,7 @@ RocksDb::~RocksDb() {
 }
 
 RocksDb RocksDb::clone() const {
-  return RocksDb{db_, statistics_};
+  return RocksDb{db_, options_};
 }
 
 Result<RocksDb> RocksDb::open(std::string path, RocksDbOptions options) {
@@ -64,16 +64,16 @@ Result<RocksDb> RocksDb::open(std::string path, RocksDbOptions options) {
   {
     rocksdb::Options db_options;
 
-    static auto cache = rocksdb::NewLRUCache(1 << 30);
+    static auto default_cache = rocksdb::NewLRUCache(1 << 30);
+    if (options.block_cache == nullptr) {
+      options.block_cache = default_cache;
+    }
 
     rocksdb::BlockBasedTableOptions table_options;
-    if (options.block_cache_size) {
-      table_options.block_cache = rocksdb::NewLRUCache(options.block_cache_size.value());
-    } else {
-      table_options.block_cache = cache;
-    }
+    table_options.block_cache = options.block_cache;
     db_options.table_factory.reset(rocksdb::NewBlockBasedTableFactory(table_options));
 
+    db_options.use_direct_reads = options.use_direct_reads;
     db_options.manual_wal_flush = true;
     db_options.create_if_missing = true;
     db_options.max_background_compactions = 4;
@@ -94,7 +94,7 @@ Result<RocksDb> RocksDb::open(std::string path, RocksDbOptions options) {
     // default column family
     delete handles[0];
   }
-  return RocksDb(std::shared_ptr<rocksdb::OptimisticTransactionDB>(db), std::move(options.statistics));
+  return RocksDb(std::shared_ptr<rocksdb::OptimisticTransactionDB>(db), std::move(options));
 }
 
 std::shared_ptr<rocksdb::Statistics> RocksDb::create_statistics() {
@@ -109,6 +109,10 @@ void RocksDb::reset_statistics(const std::shared_ptr<rocksdb::Statistics> statis
   statistics->Reset();
 }
 
+std::shared_ptr<rocksdb::Cache> RocksDb::create_cache(size_t capacity) {
+  return rocksdb::NewLRUCache(capacity);
+}
+
 std::unique_ptr<KeyValueReader> RocksDb::snapshot() {
   auto res = std::make_unique<RocksDb>(clone());
   res->begin_snapshot().ensure();
@@ -120,7 +124,6 @@ std::string RocksDb::stats() const {
   db_->GetProperty("rocksdb.stats", &out);
   //db_->GetProperty("rocksdb.cur-size-all-mem-tables", &out);
   return out;
-  return statistics_->ToString();
 }
 
 Result<RocksDb::GetStatus> RocksDb::get(Slice key, std::string &value) {
@@ -187,6 +190,28 @@ Result<size_t> RocksDb::count(Slice prefix) {
   return res;
 }
 
+Status RocksDb::for_each(std::function<Status(Slice, Slice)> f) {
+  rocksdb::ReadOptions options;
+  options.snapshot = snapshot_.get();
+  std::unique_ptr<rocksdb::Iterator> iterator;
+  if (snapshot_ || !transaction_) {
+    iterator.reset(db_->NewIterator(options));
+  } else {
+    iterator.reset(transaction_->GetIterator(options));
+  }
+
+  iterator->SeekToFirst();
+  for (; iterator->Valid(); iterator->Next()) {
+    auto key = from_rocksdb(iterator->key());
+    auto value = from_rocksdb(iterator->value());
+    TRY_STATUS(f(key, value));
+  }
+  if (!iterator->status().ok()) {
+    return from_rocksdb(iterator->status());
+  }
+  return Status::OK();
+}
+
 Status RocksDb::begin_write_batch() {
   CHECK(!transaction_);
   write_batch_ = std::make_unique<rocksdb::WriteBatch>();
@@ -243,7 +268,7 @@ Status RocksDb::end_snapshot() {
   return td::Status::OK();
 }
 
-RocksDb::RocksDb(std::shared_ptr<rocksdb::OptimisticTransactionDB> db, std::shared_ptr<rocksdb::Statistics> statistics)
-    : db_(std::move(db)), statistics_(std::move(statistics)) {
+RocksDb::RocksDb(std::shared_ptr<rocksdb::OptimisticTransactionDB> db, RocksDbOptions options)
+    : db_(std::move(db)), options_(options) {
 }
 }  // namespace td
diff --git a/tddb/td/db/RocksDb.h b/tddb/td/db/RocksDb.h
index babfadb73..5efcd0f48 100644
--- a/tddb/td/db/RocksDb.h
+++ b/tddb/td/db/RocksDb.h
@@ -27,6 +27,7 @@
 #include "td/utils/optional.h"
 
 namespace rocksdb {
+class Cache;
 class OptimisticTransactionDB;
 class Transaction;
 class WriteBatch;
@@ -38,7 +39,8 @@ namespace td {
 
 struct RocksDbOptions {
   std::shared_ptr<rocksdb::Statistics> statistics = nullptr;
-  optional<uint64> block_cache_size;  // Default - one 1G cache for all RocksDb
+  std::shared_ptr<rocksdb::Cache> block_cache;  // Default - one 1G cache for all RocksDb
+  bool use_direct_reads = false;
 };
 
 class RocksDb : public KeyValue {
@@ -51,6 +53,7 @@ class RocksDb : public KeyValue {
   Status set(Slice key, Slice value) override;
   Status erase(Slice key) override;
   Result<size_t> count(Slice prefix) override;
+  Status for_each(std::function<Status(Slice, Slice)> f) override;
 
   Status begin_write_batch() override;
   Status commit_write_batch() override;
@@ -71,6 +74,8 @@ class RocksDb : public KeyValue {
   static std::string statistics_to_string(const std::shared_ptr<rocksdb::Statistics> statistics);
   static void reset_statistics(const std::shared_ptr<rocksdb::Statistics> statistics);
 
+  static std::shared_ptr<rocksdb::Cache> create_cache(size_t capacity);
+
   RocksDb(RocksDb &&);
   RocksDb &operator=(RocksDb &&);
   ~RocksDb();
@@ -81,7 +86,7 @@ class RocksDb : public KeyValue {
 
  private:
   std::shared_ptr<rocksdb::OptimisticTransactionDB> db_;
-  std::shared_ptr<rocksdb::Statistics> statistics_;
+  RocksDbOptions options_;
 
   std::unique_ptr<rocksdb::Transaction> transaction_;
   std::unique_ptr<rocksdb::WriteBatch> write_batch_;
@@ -94,7 +99,6 @@ class RocksDb : public KeyValue {
   };
   std::unique_ptr<const rocksdb::Snapshot, UnreachableDeleter> snapshot_;
 
-  explicit RocksDb(std::shared_ptr<rocksdb::OptimisticTransactionDB> db,
-                   std::shared_ptr<rocksdb::Statistics> statistics);
+  explicit RocksDb(std::shared_ptr<rocksdb::OptimisticTransactionDB> db, RocksDbOptions options);
 };
 }  // namespace td
diff --git a/validator-engine/validator-engine.cpp b/validator-engine/validator-engine.cpp
index 0c423f7a9..06ca89b56 100644
--- a/validator-engine/validator-engine.cpp
+++ b/validator-engine/validator-engine.cpp
@@ -1372,6 +1372,8 @@ td::Status ValidatorEngine::load_global_config() {
   if (celldb_cache_size_) {
     validator_options_.write().set_celldb_cache_size(celldb_cache_size_.value());
   }
+  validator_options_.write().set_celldb_direct_io(celldb_direct_io_);
+  validator_options_.write().set_celldb_preload_all(celldb_preload_all_);
   if (catchain_max_block_delay_) {
     validator_options_.write().set_catchain_max_block_delay(catchain_max_block_delay_.value());
   }
@@ -3984,6 +3986,14 @@ int main(int argc, char *argv[]) {
         acts.push_back([&x, v]() { td::actor::send_closure(x, &ValidatorEngine::set_celldb_cache_size, v); });
         return td::Status::OK();
       });
+  p.add_option('\0', "celldb-direct-io", "enable direct I/O mode for RocksDb in CellDb", [&]() {
+    acts.push_back([&x]() { td::actor::send_closure(x, &ValidatorEngine::set_celldb_direct_io); });
+  });
+  p.add_option(
+      '\0', "celldb-preload-all",
+      "preload all cells from CellDb on startup (recommended to use with big enough celldb-cache-size and "
+      "celldb-direct-io)",
+      [&]() { acts.push_back([&x]() { td::actor::send_closure(x, &ValidatorEngine::set_celldb_preload_all); }); });
   p.add_checked_option(
       '\0', "catchain-max-block-delay", "delay before creating a new catchain block, in seconds (default: 0.5)",
       [&](td::Slice s) -> td::Status {
diff --git a/validator-engine/validator-engine.hpp b/validator-engine/validator-engine.hpp
index 265bb9e40..94ced8ba3 100644
--- a/validator-engine/validator-engine.hpp
+++ b/validator-engine/validator-engine.hpp
@@ -210,6 +210,8 @@ class ValidatorEngine : public td::actor::Actor {
   bool disable_rocksdb_stats_ = false;
   bool nonfinal_ls_queries_enabled_ = false;
   td::optional<td::uint64> celldb_cache_size_;
+  bool celldb_direct_io_ = false;
+  bool celldb_preload_all_ = false;
   td::optional<double> catchain_max_block_delay_;
   bool read_config_ = false;
   bool started_keyring_ = false;
@@ -286,6 +288,12 @@ class ValidatorEngine : public td::actor::Actor {
   void set_celldb_cache_size(td::uint64 value) {
     celldb_cache_size_ = value;
   }
+  void set_celldb_direct_io() {
+    celldb_direct_io_ = true;
+  }
+  void set_celldb_preload_all() {
+    celldb_preload_all_ = true;
+  }
   void set_catchain_max_block_delay(double value) {
     catchain_max_block_delay_ = value;
   }
diff --git a/validator/db/celldb.cpp b/validator/db/celldb.cpp
index bc315b599..dfbee0a1a 100644
--- a/validator/db/celldb.cpp
+++ b/validator/db/celldb.cpp
@@ -91,9 +91,10 @@ void CellDbIn::start_up() {
   td::RocksDbOptions db_options;
   db_options.statistics = statistics_;
   if (opts_->get_celldb_cache_size()) {
-    db_options.block_cache_size = opts_->get_celldb_cache_size().value();
-    LOG(WARNING) << "Set CellDb block cache size to " << td::format::as_size(db_options.block_cache_size.value());
+    db_options.block_cache = td::RocksDb::create_cache(opts_->get_celldb_cache_size().value());
+    LOG(WARNING) << "Set CellDb block cache size to " << td::format::as_size(opts_->get_celldb_cache_size().value());
   }
+  db_options.use_direct_reads = opts_->get_celldb_direct_io();
   cell_db_ = std::make_shared<td::RocksDb>(td::RocksDb::open(path_, std::move(db_options)).move_as_ok());
 
 
@@ -111,6 +112,27 @@ void CellDbIn::start_up() {
     set_block(empty, std::move(e));
     cell_db_->commit_write_batch().ensure();
   }
+
+  if (opts_->get_celldb_preload_all()) {
+    // Iterate whole DB in a separate thread
+    delay_action([snapshot = cell_db_->snapshot()]() {
+      LOG(WARNING) << "CellDb: pre-loading all keys";
+      td::uint64 total = 0;
+      td::Timer timer;
+      auto S = snapshot->for_each([&](td::Slice, td::Slice) {
+        ++total;
+        if (total % 1000000 == 0) {
+          LOG(INFO) << "CellDb: iterated " << total << " keys";
+        }
+        return td::Status::OK();
+      });
+      if (S.is_error()) {
+        LOG(ERROR) << "CellDb: pre-load failed: " << S.move_as_error();
+      } else {
+      LOG(WARNING) << "CellDb: iterated " << total << " keys in " << timer.elapsed() << "s";
+      }
+    }, td::Timestamp::now());
+  }
 }
 
 void CellDbIn::load_cell(RootHash hash, td::Promise<td::Ref<vm::DataCell>> promise) {
diff --git a/validator/validator-options.hpp b/validator/validator-options.hpp
index 34f7fdf9f..593c75bf6 100644
--- a/validator/validator-options.hpp
+++ b/validator/validator-options.hpp
@@ -132,6 +132,12 @@ struct ValidatorManagerOptionsImpl : public ValidatorManagerOptions {
   td::optional<td::uint64> get_celldb_cache_size() const override {
     return celldb_cache_size_;
   }
+  bool get_celldb_direct_io() const override {
+    return celldb_direct_io_;
+  }
+  bool get_celldb_preload_all() const override {
+    return celldb_preload_all_;
+  }
   td::optional<double> get_catchain_max_block_delay() const override {
     return catchain_max_block_delay_;
   }
@@ -206,6 +212,12 @@ struct ValidatorManagerOptionsImpl : public ValidatorManagerOptions {
   void set_celldb_cache_size(td::uint64 value) override {
     celldb_cache_size_ = value;
   }
+  void set_celldb_direct_io(bool value) override {
+    celldb_direct_io_ = value;
+  }
+  void set_celldb_preload_all(bool value) override {
+    celldb_preload_all_ = value;
+  }
   void set_catchain_max_block_delay(double value) override {
     catchain_max_block_delay_ = value;
   }
@@ -257,6 +269,8 @@ struct ValidatorManagerOptionsImpl : public ValidatorManagerOptions {
   bool disable_rocksdb_stats_;
   bool nonfinal_ls_queries_enabled_ = false;
   td::optional<td::uint64> celldb_cache_size_;
+  bool celldb_direct_io_ = false;
+  bool celldb_preload_all_ = false;
   td::optional<double> catchain_max_block_delay_;
 };
 
diff --git a/validator/validator.h b/validator/validator.h
index 81dfe7a39..245acbd49 100644
--- a/validator/validator.h
+++ b/validator/validator.h
@@ -87,6 +87,8 @@ struct ValidatorManagerOptions : public td::CntObject {
   virtual bool get_disable_rocksdb_stats() const = 0;
   virtual bool nonfinal_ls_queries_enabled() const = 0;
   virtual td::optional<td::uint64> get_celldb_cache_size() const = 0;
+  virtual bool get_celldb_direct_io() const = 0;
+  virtual bool get_celldb_preload_all() const = 0;
   virtual td::optional<double> get_catchain_max_block_delay() const = 0;
 
   virtual void set_zero_block_id(BlockIdExt block_id) = 0;
@@ -113,6 +115,8 @@ struct ValidatorManagerOptions : public td::CntObject {
   virtual void set_disable_rocksdb_stats(bool value) = 0;
   virtual void set_nonfinal_ls_queries_enabled(bool value) = 0;
   virtual void set_celldb_cache_size(td::uint64 value) = 0;
+  virtual void set_celldb_direct_io(bool value) = 0;
+  virtual void set_celldb_preload_all(bool value) = 0;
   virtual void set_catchain_max_block_delay(double value) = 0;
 
   static td::Ref<ValidatorManagerOptions> create(