On Wed, Jul 27, 2011 at 8:58 AM, 吴限 <[email protected]> wrote: > Setup: > -cdh3u0 > - Hadoop 0.20.2
You are using the hadoop from cdh3u0? > - dfs.replication is set to 1 > You will lose data if a machine goes away. You have two machines but only one instance of each data block; think of it as half of your data one one node and the rest on another. If you kill one machine, half your data is gone. > After I restarted the regionserver which I had rebooted and checked again, > I found that some of the missing data was got back but there still existed > some data which hadn't been found yet. I wonder what was going on here that we didn't see it all restored. > This is problematic since we are supposed to > replicate at x1, so at least one other node should be able to > theoretically serve the *data* that the downed regionserver can't. > No. The behavior you describe would come with replication of 2, not 1. St.Ack
