diff --git a/fdbserver/KeyValueStoreRocksDB.actor.cpp b/fdbserver/KeyValueStoreRocksDB.actor.cpp
index 7a3a6afe5e..3ae8d6c84d 100644
--- a/fdbserver/KeyValueStoreRocksDB.actor.cpp
+++ b/fdbserver/KeyValueStoreRocksDB.actor.cpp
@@ -92,7 +92,7 @@ struct RocksDBKeyValueStore : IKeyValueStore {
 		};
 		void action(CommitAction& a) {
 			rocksdb::WriteOptions options;
-			options.sync = true;
+			options.sync = !SERVER_KNOBS->ROCKSDB_UNSAFE_AUTO_FSYNC;
 			auto s = db->Write(options, a.batchToCommit.get());
 			if (!s.ok()) {
 				TraceEvent(SevError, "RocksDBError").detail("Error", s.ToString()).detail("Method", "Commit");
diff --git a/fdbserver/Knobs.cpp b/fdbserver/Knobs.cpp
index 120c960102..b5a15d6ca0 100644
--- a/fdbserver/Knobs.cpp
+++ b/fdbserver/Knobs.cpp
@@ -311,6 +311,7 @@ void ServerKnobs::initialize(bool randomize, ClientKnobs* clientKnobs, bool isSi
 	// KeyValueStoreRocksDB
 	init( ROCKSDB_BACKGROUND_PARALLELISM,                          0 );
 	init( ROCKSDB_MEMTABLE_BYTES,                  512 * 1024 * 1024 );
+	init( ROCKSDB_UNSAFE_AUTO_FSYNC,                           false );
 
 	// Leader election
 	bool longLeaderElection = randomize && BUGGIFY;
diff --git a/fdbserver/Knobs.h b/fdbserver/Knobs.h
index 61d0969333..2ea5660154 100644
--- a/fdbserver/Knobs.h
+++ b/fdbserver/Knobs.h
@@ -246,6 +246,7 @@ public:
 	// KeyValueStoreRocksDB
 	int ROCKSDB_BACKGROUND_PARALLELISM;
 	int64_t ROCKSDB_MEMTABLE_BYTES;
+	bool ROCKSDB_UNSAFE_AUTO_FSYNC;
 
 	// Leader election
 	int MAX_NOTIFICATIONS;