CODEWITHSUNDEEP
hadoophdfshbase
Shellong
Shellong

Reputation: 381

HBase store file storage location

Each Region Server in HBase is assigned some regions of some tables. These Region Servers may have many regions, and their corresponding Store files have replicas on other HDFS Datanodes.

If one Region Server goes down, then HMaster will assign another server to takeover and serve the offlined regions.

My question is -- are the missing regions' store files all stored on one Region Server?

Upvotes: 1

Views: 610

Answers (2)

mazaneicha
mazaneicha

Reputation: 9427

Paraphrasing and expanding @ramachandran-a-g 's answer a little: any Region Server can access data of any region since all data is stored in HDFS. However, for better performance Region Servers are concerned with (historically, since early Hadoop days) and keep track of data locality, i.e. whether region's store files are present in local HDFS Data Node or not. The RS metric, hbase.regionserver.percentFilesLocal, shows the "Percent of store file data that can be read from the local DataNode, 0-100".

Upvotes: 2

Ramachandran.A.G
Ramachandran.A.G

Reputation: 4948

If I understand it right , the question is where is the data that is pointed to from the RS stored.

From the documentation : https://hbase.apache.org/book.html#config.files

Just as in pseudo-distributed mode, a fully distributed configuration requires that you set the hbase.cluster.distributed property to true. Typically, the hbase.rootdir is configured to point to a highly-available HDFS filesystem.

and also

hbase.rootdir : Description

The directory shared by region servers and into which HBase persists. The URL should be 'fully-qualified' to include the filesystem scheme. For example, to specify the HDFS directory '/hbase' where the HDFS instance’s namenode is running at namenode.example.org on port 9000, set this value to: hdfs://namenode.example.org:9000/hbase. By default, we write to whatever ${hbase.tmp.dir} is set too — usually /tmp — so change this configuration or else all data will be lost on machine restart.

Upvotes: 1

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