That question is sort of orthogonal to the first one... Please create a new thread if you want to change the subject.
HBase uses the DFSClient, for example if HBase needs to open a file it needs to talk to the NN first (through the DFSClient, HBase doesn't really know what's going on). J-D On Wed, Sep 21, 2011 at 2:06 AM, shanmuganathan.r <[email protected]> wrote: > Hi Jack, > > I understood this concept. The DFS client is directly connected to > the datanodes in hdfs and perform the read/write block data with communicate > with the namenode by client protocol . Is there is no direct involvement of > > > namenode in the HBase operation ? > > Thanks > > R.Shanmuganathan > > > > ---- On Wed, 21 Sep 2011 12:55:37 +0530 Jack Levin<[email protected]> > wrote ---- > > > The master will detect that RS is down by periodically checking a > zookeeper ( it will say in the master log, znode expired ). After, it > will check to see if there is anything in /hbase/.logs directory for > that region server, if something is found, master will replay the log > records and 'push' them into region directories, when master is done, > the 'unopened' regions will be opened by the rest of the region > servers and all regions that were down will be back online. > > -Jack > > On Wed, Sep 21, 2011 at 12:21 AM, shanmuganathan.r > <[email protected]> wrote: > > Hi All, > > > > I am running the HBase in fully distributed mode. I used the > HBase 0.90.2 version . I have one doubt , that one is what will happen when > the Region server is crashed ? > > > > > > If the one region is managed by one region server then what will happen > after the crash of the region server? > > > > Thanks in Advance.... > > > > > > Regards > > > > > > R.Shanmuganathan > > > > > > > >
