diff --git a/Directories-and-Files.md b/Directories-and-Files.md
index 63b5f38..fbf26de 100644
--- a/Directories-and-Files.md
+++ b/Directories-and-Files.md
@@ -79,7 +79,8 @@ The Filer Store persists all file metadata and directory information.
 | Filer Store Name | Lookup | number of entries in a folder | Scalability | Renaming | TTL | Note |
 | ---------------- | -- | -- | -- | -- | -- | -- |
 | memory       | O(1)   | limited by memory | Local, Fast                | | | for testing only, no persistent storage |
-| LevelDB      | O(logN)| unlimited | Local, Very Fast               | | | Default, fairly scalable |
+| leveldb      | O(logN)| unlimited | Local, Very Fast               | | | Default, fairly scalable |
+| leveldb2     | O(logN)| unlimited | Local, Very Fast, faster than leveldb          | | | Similar to leveldb, the lookup key is 128bit full filename MD5 instead of the long full file name |
 | Redis        | O(1)   | limited   | Local or Distributed, Fastest  ||Yes| one directory's sub file names are stored in one key~value entry |
 | Cassandra    | O(logN)| unlimited | Local or Distributed, Very Fast||Yes|                |
 | MySql        | O(logN)| unlimited | Local or Distributed, Fast     |Atomic| | Easy to manage, export |