Does anybody know the state of the Backupnamenode scheme that is referenced here? I am looking for a Jira ticket that might give me some more insight into the timeline for release. The hadoop-general email list doesn't seem to have any information about this issue, which is kind of worrying...
TIA. -- Andrew On Tue, 2009-06-02 at 16:57 +0200, ext Jean-Daniel Cryans wrote: > Andrew, > > I think you are confusing some components of the whole stack here. The > Namenode is the master for HDFS just like the HMaster is the master > for HBase. Hadoop is 2 things : HDFS and an implementation of > MapReduce which also has a master, the JobTracker. HBase sits on all > that. > > So with regards with what's fixed, the HMaster SPOF is fixed for 0.20. > The Namenode in 0.20 is still a SPOF. That means, if you want HA, you > should get a really reliable machine for the Namenode but you can put > the HMaster on any nodes you want. > AFAIK, there is a BackupNamenode in Hadoop 0.21 that serves as a > Namenode failover.
