diff --git a/benchmark_main.go b/benchmark_main.go
index 256a5207f..eb8ff2578 100644
--- a/benchmark_main.go
+++ b/benchmark_main.go
@@ -85,16 +85,6 @@ func main() {
 
 	// Setup a logger to stdout and log file.
 	logFileName := fmt.Sprintf("./%v/%v.log", *logFolder, *port)
-	_, err := os.Stat(logFileName)
-	if err == nil {
-		fmt.Printf("file %s exists", logFileName)
-		os.Remove(logFileName)
-		fmt.Printf("removed file %s", logFileName)
-	} else if os.IsNotExist(err) {
-		fmt.Printf("file %s not exists", logFileName)
-	} else {
-		fmt.Printf("file %s stat error: %v", logFileName, err)
-	}
 	h := log.MultiHandler(
 		log.Must.FileHandler(logFileName, log.LogfmtFormat()),
 		log.StdoutHandler)
diff --git a/deploy_one_instance.sh b/deploy_one_instance.sh
index 688dc8cec..4a4060288 100755
--- a/deploy_one_instance.sh
+++ b/deploy_one_instance.sh
@@ -22,8 +22,15 @@ echo ">>>>"
 python aws-scripts/preprocess_peerlist.py 
 FILE='isTransaction.txt'
 config=$1
-log_folder=logs/
-mkdir -p $log_folder
+
+t=`date +"%Y%m%d-%H%M%S"`
+log_folder="logs/log-$t"
+
+if [ ! -d $log_folder ] 
+then
+    mkdir -p $log_folder
+fi
+
 if [ -f $FILE ]; then
     go run ./aws-code/transaction_generator.go -config_file $config -log_folder $log_folder&
 else