[Hadoop Wiki] Update of "HdfsFutures" by SanjayRadia

[Apache Wiki <wi...@apache.org>]

Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Hadoop Wiki" for change notification.

The "HdfsFutures" page has been changed by SanjayRadia.
http://wiki.apache.org/hadoop/HdfsFutures?action=diff&rev1=8&rev2=9

--------------------------------------------------

     * Read-only Replicas of NN
        * Scales performance but not namespace
        * Adds reliability and one of the steps towards HA
-    * Partition Namespace: Multiple namespace volumes
+    * Partition Namespace statically: Multiple namespace volumes
        * Scales both
        * Retains HDFS’s design philosophy but need a simplified automounter and management of horizontal scaling of NN servers
+    * A truly distributed name server that automatically partitions the namespace dynamically 
     * Split function on NN (Namespace and Block maps)
        * scales name space x3, a little performance scaling
     * Page-in partial name space from disk (as in traditional FSs)
@@ -118, +119 @@

  
  Partition/distribute Name node (will also help performance)
     <<BR>>Several Options:
-    * Partition the namespace hierarchically and mount the volumes
+    * Statically Partition the namespace hierarchically and mount the volumes
        * In this scheme, there are multiple namespace volumes in a cluster.
        * All the name space volumes share the physical block storage (i.e. One storage pool)
        * Optionally All namespaces (ie volumes) are mounted at top level using an automounter like approach
        * A namepace can be explicitly mounted on to a node in another namename (a la mount in Posix)
           * Note the Cepf file system [ref] partitions automatically and mounts the partition
  
-    * Partition by a hash function - clients go to one NN by hashing the name
+    * A truly distributed name service that partitions the namespace dynamically.
  
     *    Only keep part of the namespace in memory.
        * This like a tradional file system where the entire namepsace is stored in secondary and page-in as needed.