> Will upgrading to 0.89 be a PITA? Unless you still use the deprecated APIs, it's actually just a matter of replacing the distribution and restarting.
> > Should we expect to be able to upgrade the servers without losing data? Definitely, since no upgrade of the filesystem format is required. But it's always a good practice to backup your data before any upgrade. > > Will there be tons of client code changes? See first answer. > > What about configuration changes (especially little changes that will bite > us)? When we upgraded we only added dfs.support.append set to true. > > Do we need/want to upgrade hadoop at all (we're on 0.20.2)? If you want data durability (eg no data loss), yes. > > If we do upgrade, what is the recommended package to get it from? We use CDH3b2's hadoop, I'd recommend that, but you can also use the head of the Hadoop 0.20-append branch. We have our own HBase "distro" that we publish here http://github.com/stumbleupon/hbase, this is what's currently in production. It's not much different from 0.89.20100924 (which is still RC1), mainly fixes and improvements for cluster replication that will eventually make it to core hbase, and some neat changes to the ThriftServer to enable async ICVs. J-D
