Hi Edward You mean restoring data means all the stored data when the regionservers were running fine?
Yes, HBase will restore you all the data that was being served by the failed region server by replaying the HLog which will be done by the master. Regards Ram -----Original Message----- From: edward choi [mailto:[email protected]] Sent: Wednesday, October 12, 2011 3:05 PM To: [email protected]; [email protected] Subject: Does Hbase automatically restore data when regionservers fail? Hi, I am using CDH3U0 Hadoop and Hbase. I know that HDFS automatically replicates data to multiple data nodes so that when a couple of data nodes fail, the user won't lose any data. I am currently using replication factor of 3. Now in Hbase, I know there is some experimental replication service, but I am not using it. I thought that since HDFS already does replication, Hbase wouldn't need additional replication. Am I right on this? So my question would be: Given that I am using HDFS replication and not using Hbase replication, if a couple of regionservers fail, am I still able to access all the data I have stored before? I would appreciate any help. Thanks. Ed
