Hbase .META table

Question

I have a doubt regarding the location of Hbase -ROOT- table and .META table .I have read that the Hbase -ROOT- table resides in the znode of the zookeeper , So when the client query the -ROOT- the information of the server hosting the .META is found . My doubt is does the .META reside in one single server. If so if that server crashes the information of .META table is lost. Or am I wrong ? Could any one help.

This is my reference: https://blog.safaribooksonline.com/2012/11/16/tip-2-hbase-meta-layout/

Answer 1

As mentioned in The Apache HBase Reference Guide The -ROOT- table is removed since HBase 0.96.0 and the location of .META table is currently stored in the Zookeeper and its name become hbase:meta

Currently the Meta data resides on a single server, but there is an Open Ticket to replicate the hbase:meta's regions.

However, HBase makes a few things to overcome this shortage:

1. It gives a higher priority to make the META get online when a failure occurs
2. The information about hbase:meta is cached by the client for future interactions and is refreshed only if the regions it’s expecting to interact with based on that information don’t exist on the node it thinks they should be on. (from HBase In Action : 3.3.2 How do I find my region?), so if the Meta region went offline only requests to .META. fail.