diff --git a/config/config.go b/config/config.go
index 48a45f7..ca93d29 100644
--- a/config/config.go
+++ b/config/config.go
@@ -102,6 +102,7 @@ func NewConfigDefault() *Config {
 	// disable access log
 	cfg.AccessLog = ""
 
+	cfg.LMDB.MapSize = 20 * 1024 * 1024
 	cfg.LMDB.NoSync = true
 
 	return cfg
diff --git a/config/config.toml b/config/config.toml
index 573db9a..2a3a246 100644
--- a/config/config.toml
+++ b/config/config.toml
@@ -22,6 +22,8 @@ slaveof = ""
 #   goleveldb
 #   lmdb
 #   boltdb
+#   hyperleveldb
+#   memory
 #   
 db_name = "leveldb"
 
diff --git a/etc/ledis.conf b/etc/ledis.conf
index 2097f65..d3adbd8 100644
--- a/etc/ledis.conf
+++ b/etc/ledis.conf
@@ -24,6 +24,8 @@ slaveof = ""
 #   goleveldb
 #   lmdb
 #   boltdb
+#   hyperleveldb
+#   memory
 #   
 db_name = "leveldb"