On Sun, Sep 26, 2010 at 12:21 PM, Andrey Timerbaev <[email protected]> wrote: > Dear All, > > In my Hadoop 0.20.1/HBase 0.20.3 cluster I’ve got 2 region servers. On each > region server, Hadoop DataNode and HBase RegionServer processes are running. > Hadoop is set up redundantly (it writes each data to both DataNodes, i.e. > writes > data with replication factor 2). But as per information from the HBase Web UI, > HBase creates on the region servers unique regions. E.g. tables A, B are > created > on region server 1, and tables C, D are created on the region server 2. Next, > I > noticed, when region server 1 is not available, the tables A and B are not > available as well (cannot be read/written to). > > Could you kindly suggest, how to make HBase redundant, so that all tables are > available even if one of region servers fails/dies? > Have I missed a Hadoop/HBase setting to do so? > > Thank you, > Andrey Timerbaev > > >
In case when one of regionservers fail, HBase Master will reassign all regions, so, any regions served by failed regionserver will be assigned to operating regionservers. It is possible because of replication on datanodes, regionserver heartbeats and Write-Ahead-Logs. HBase master can be made redundant too. -- Regards, Stanislaw Kogut Sistyma LLC
