/mnesia-clustering-test

Primary LanguageErlang

Mnesia Clustering#

This document describes how to

  • Initialize DB replicated Mnesia cluster
  • Dynamically add Mnesia node to existing Mnesia cluster

Sample Program

The sample program code base is from Erlang replication test and was modified based on 分散DBMS「Mnesia」の並列処理(Japanese) .

Prerequesites

  • Erlang runtime installed.
  • Nodes initialized
    • Create node folders (e.g. node1, node2,...)
    • Copy test_mnesia.erl to created node folders
    • erl -sname <node_name>
    • (node_name@hostname)1> c(test_mnesia).

##Add cluster nodes at beginning##

Given 2 nodes, Node1 and Node2

####Node1####

  1. Connect to node2
  2. Create schema and table. This step add schema and table to every nodes connected to node1
  3. Start Mnesia database
  4. Add testing data
test_mnesia:connect_node('node2@hostname').
test_mnesia:create_schema_and_table(). 
test_mnesia:start().
test_mnesia:add_test_data().

####Node2####

  1. Start Mnesia database
  2. Validate if data replicated to node2 successfully.
test_mnesia:start().
test_mnesia:show_shop_table().

Add cluster nodes by change_config

####Node2####

test_mnesia:start().

The function is a blocking code with N minute timeout for incoming mnesia:add_table_copy() request (N is currently 2). During the timeout, switch back to Node1 for next command.

####Node1####

add_node() invokes mnesia:add_table_copy().

test_mnesia:add_node('node2@hostname').

####Node2####

Validate if data replicated to node2 successfully.

test_mnesia:show_shop_table().