Dear Stack, thx for your reply~ First I don't know if there is something wrong with the cdh3u0. And thx for ur reminding me about the replication property,which I didn't quite understand but now understands. I'll try to correct this mistake. But actually these situations which I have described really happens with the replication being set to 1. And that's why I find these quite weird . I just started trying hbase a month ago and there exist a lot of things i don't quite understand. Hope to get replied. Thanks~ 2011/7/28 Stack <[email protected]>
> 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 >
