I am planning to create a new branch from the trunk for the work related to HDFS-1052 - HDFS scalability using multiple namenodes/namespaces. Please see the jira for more details. Doing the development in a separate branch will reduce the churn on the trunk. The development will be done incrementally in the new branch using multiple sub jiras. When the development and testing is complete, the changes from this branch will be promoted back to trunk.