> In that case I guess I need multiple masters if the master node needs to be > taken down for maintenance.
To take the Namenode down you need to shutdown HDFS, so that means HBase too. Having a second Namenode ready is good only to minimize downtime if the machine dies (providing that they share some NFS folder where the fsimage is stored). This is also what cloudera recommends http://www.cloudera.com/blog/2010/03/clouderas-support-team-shares-some-basic-hardware-recommendations/ > > If a region server is taken down for maintenance will hbase rebalance the > start and end keys? It rebalances the regions yes, just like Bigtable does http://labs.google.com/papers/bigtable-osdi06.pdf J-D
