Thx for your reply. But actually later I did another experiment similar to one which I explained earlier. Step 1: I inserted some data into the hbase. Step 2: I shut one of the region servers. Step 3 : I checked the table and found some data had been lost. Step 4: I disabled the table and then enabled the table Step 5 : I checked again and found nothing lost.
If some data didn't exist in the other region server, then how can u explain this? Hope to get ur reply.Thx~ 2011/7/28 Chris Tarnas <[email protected]> > Replication of 1x means no replication. 2x would mean the data exists in > two locations (what it looks like you want). Running with a replication of > 1x is a very bad idea and is pretty much a guaranteed way to get data loss. > > -chris > > On Jul 27, 2011, at 8:58 AM, 吴限 wrote: > > > Hi everyone. I'd like to run the following *data* *loss* scenario by you > to > > see if > > we are doing something obviously wrong with our setup here. > > > > Setup: > > -cdh3u0 > > - Hadoop 0.20.2 > > - HBase 0.90.1 > > - 1 Master Node running as NameNode & JobTracker > > -zookeeper quorum > > - 2 child nodes running as Datanode, TaskTracker and RegionServer each > > - dfs.replication is set to 1 > > > > First, I inserted some data into the hbase a few hours ago. > > Then after a while. I rebooted one of the region servers and waited until > > the master responded to that. However, after I checked the table using > hbase > > shell (I used the "count" command), I noticed that there was a huge > amount > > of data being lost. > > 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. > > At last,after I disabled the table and then enabled the table , I found > that > > all data was stored in the cluster and there was no data that was lost. > > > > 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. > > > > Questions: > > > > - How can you guys explain this weird situation? > > - Are there way to recover such lost *data*? > > > > Any tips here are definitely appreciated. I'll be happy to provide more > > information as well.-0 > >
