diff --git a/fdbclient/ServerKnobs.cpp b/fdbclient/ServerKnobs.cpp
index 735bc807f7..656c22c8b0 100644
--- a/fdbclient/ServerKnobs.cpp
+++ b/fdbclient/ServerKnobs.cpp
@@ -641,12 +641,13 @@ void ServerKnobs::initialize(Randomize randomize, ClientKnobs* clientKnobs, IsSi
 	init( SHARDED_ROCKSDB_LEVEL0_FILENUM_COMPACTION_TRIGGER,       4 );
 	init( SHARDED_ROCKSDB_LEVEL0_SLOWDOWN_WRITES_TRIGGER,         20 ); // RocksDB default.
 	init( SHARDED_ROCKSDB_LEVEL0_STOP_WRITES_TRIGGER,             36 ); // RocksDB default.
-	init( SHARDED_ROCKSDB_DELAY_COMPACTION_FOR_DATA_MOVE,      false ); if (isSimulated) SHARDED_ROCKSDB_DELAY_COMPACTION_FOR_DATA_MOVE = true;
+	init( SHARDED_ROCKSDB_DELAY_COMPACTION_FOR_DATA_MOVE,      false ); // Open the knob can significantly slow down the simulation
 	init( SHARDED_ROCKSDB_MAX_OPEN_FILES,                      50000 ); // Should be smaller than OS's fd limit.
 	init (SHARDED_ROCKSDB_READ_ASYNC_IO,                       false ); if (isSimulated) SHARDED_ROCKSDB_READ_ASYNC_IO = deterministicRandom()->coinflip();
 	init( SHARDED_ROCKSDB_PREFIX_LEN,                              0 ); if( randomize && BUGGIFY )  SHARDED_ROCKSDB_PREFIX_LEN = deterministicRandom()->randomInt(1, 20);
 	init( SHARDED_ROCKSDB_HISTOGRAMS_SAMPLE_RATE,              0.001 ); if( randomize && BUGGIFY ) SHARDED_ROCKSDB_HISTOGRAMS_SAMPLE_RATE = 0;
-	init( SHARDED_ROCKSDB_USE_DIRECT_IO,                 false ); if (isSimulated) SHARDED_ROCKSDB_USE_DIRECT_IO = deterministicRandom()->coinflip();
+	init( SHARDED_ROCKSDB_USE_DIRECT_IO,                       false ); if (isSimulated) SHARDED_ROCKSDB_USE_DIRECT_IO = deterministicRandom()->coinflip();
+	init( ENFORCE_SHARDED_ROCKSDB_SIM_IF_AVALIABLE,            false ); // Turn off by default.
 
 
 	// Leader election
diff --git a/fdbclient/include/fdbclient/ServerKnobs.h b/fdbclient/include/fdbclient/ServerKnobs.h
index 7fdf2498f5..b65729bd4f 100644
--- a/fdbclient/include/fdbclient/ServerKnobs.h
+++ b/fdbclient/include/fdbclient/ServerKnobs.h
@@ -619,6 +619,7 @@ public:
 	int SHARDED_ROCKSDB_PREFIX_LEN;
 	double SHARDED_ROCKSDB_HISTOGRAMS_SAMPLE_RATE;
 	bool SHARDED_ROCKSDB_USE_DIRECT_IO;
+	bool ENFORCE_SHARDED_ROCKSDB_SIM_IF_AVALIABLE; // set to enforce shardedrocks in simulation as much as possible
 
 	// Leader election
 	int MAX_NOTIFICATIONS;
diff --git a/fdbserver/SimulatedCluster.actor.cpp b/fdbserver/SimulatedCluster.actor.cpp
index f4aa2535bf..36c79860db 100644
--- a/fdbserver/SimulatedCluster.actor.cpp
+++ b/fdbserver/SimulatedCluster.actor.cpp
@@ -1846,7 +1846,12 @@ SimulationStorageEngine chooseSimulationStorageEngine(const TestConfig& testConf
 	StringRef reason;
 	SimulationStorageEngine result = SimulationStorageEngine::SIMULATION_STORAGE_ENGINE_INVALID_VALUE;
 
-	if (testConfig.storageEngineType.present()) {
+	if (isEncryptionEnabled) {
+		// Only storage engine supporting encryption is Redwood.
+		reason = "EncryptionEnabled"_sr;
+		result = SimulationStorageEngine::REDWOOD;
+
+	} else if (testConfig.storageEngineType.present()) {
 		reason = "ConfigureSpecified"_sr;
 		result = testConfig.storageEngineType.get();
 		if (testConfig.excludedStorageEngineType(result) ||
@@ -1856,6 +1861,13 @@ SimulationStorageEngine chooseSimulationStorageEngine(const TestConfig& testConf
 			TraceEvent(SevError, "StorageEngineNotSupported").detail("StorageEngineType", result);
 			ASSERT(false);
 		}
+
+	} else if (SERVER_KNOBS->ENFORCE_SHARDED_ROCKSDB_SIM_IF_AVALIABLE &&
+	           testConfig.storageEngineExcludeTypes.find(SimulationStorageEngine::SHARDED_ROCKSDB) ==
+	               testConfig.storageEngineExcludeTypes.end()) {
+		reason = "ENFORCE_SHARDED_ROCKSDB_SIM_IF_AVALIABLE is enabled"_sr;
+		result = SimulationStorageEngine::SHARDED_ROCKSDB;
+
 	} else {
 		std::unordered_set<SimulationStorageEngine> storageEngineAvailable;
 		for (const auto& storageEngine : SIMULATION_STORAGE_ENGINE) {
@@ -1897,12 +1909,6 @@ SimulationStorageEngine chooseSimulationStorageEngine(const TestConfig& testConf
 		}
 	}
 
-	if (isEncryptionEnabled) {
-		// Only storage engine supporting encryption is Redwood.
-		reason = "EncryptionEnabled"_sr;
-		result = SimulationStorageEngine::REDWOOD;
-	}
-
 	TraceEvent(SevInfo, "SimulationStorageEngine")
 	    .detail("StorageEngine", static_cast<uint8_t>(result))
 	    .detail("Reason", reason)