That is strange behavior. How long did you wait between Step 2 and 3, and what is the results of running
hbase hbck at step 3? -chris On Jul 27, 2011, at 9:23 AM, 吴限 wrote: > 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 >> >>
