MySQL Clusters

MySQL-NDB-Cluster-based configuration


  • Build and operate nonstop system with high availability approximately 99.999%
  • Implement high-performance database which combines the best properties of current hard disk drives (HDD) and main memory
  • Very fast and automatic FailOver System
  • Flexible, parallel distributed architecture system
  • Cheap construction expenses and maintenance costs that do not require separate licenses and expenses

Necessity of MySQL Cluster

Limitations of extending MySQL-Replication: Because data entry and updates depends on the master server, when expending system, expansion of the slave server is easy, but expansion of the master server is somewhat constrained. When implementing clusters, server group of SQL-Node is implemented by each server that handles both data input/ output.

How to Implement

Require a total of three server groups(Node) for MySQL Cluster server configuration.

Management Node(Primary ↔ Standby) - Data Node(A,B,C) - SQL Node - Application Data(A,B,C)
  1. MGM-Node
    Responsible for the overall management of the cluster configuration.
    • Cluster Status Monitoring (check status of each node)
    • Backup management of the configured database
    Among Management Server, one acts as the Primary Server, and if failure occurs while working, missions will be carried out in Standby Server.
  2. Data-Node
    They play a role in storing input database. All databases which are stored in each node are kept in memory to support a rapid response. (Habiro provides a proper memory.) It is possible to save the hard disc based on new released version, from MySQL5.1 or higher.(even create ndb based on disk, the column that contains the index is stored in the memory.)
    • Responsible for physical data storage
    • Replication / partitioning / Failover application processing
    • Add or remove Data Node online is impossible (Restart the cluster if necessary)
  3. SQL-Node
    Plays a role in responding to the request of the data of Data-Node Application or forwarding stored data to Data-Node.
The minimum specifications for the construction are available with three servers, the minimum recommended specifications need a total of 6 or more servers for nonstop systems..
  • Minimum Requirements : 1 Management-Node, 1 Data-Node, 1 SQL-Node
  • Recommended Requirements : 2 Management-Nodes, 2 Data-Nodes, 2 SQL-Nodes
(Additional expansion of Data-Node and SQL-Node server group is possible according to used scale.)

MySQL- Replication-based configuration


Mysql-Replication is used for real-time synchronizing data of MySQL server set as the master and data in a number of MySQL server set as Slave to backup and load balancing. Use it to configure the two master servers and when updating data, the technology can be applied equally to each of the master server.

Necessity of Dual-Master-Replication

  • Vulnerability of single Master&Slave-Replication: When master server has error, reconfiguring master server will be done manually.
  • Intuitive service environment compared to the Mysql-Cluster: Because the data is existing as explicit files, when restoring data or doing something else, the work can be done faster and more flexible thanks to the situation.

Implementation method

Method 1

Because both master servers behave the same so when one of them has failed, the left server will continue to save the same data, and load can be distributed by application access.

Master-Server 두 대가 동일하게 작동
Method 2

One of two master servers will act as the Primary Server and when an error occurs, missions will be carried out in Standby Server. Data input(Insert, Update, Delete) are done at both the master servers, Data Import(Select) is in charge of the slave servers, so Select query can achieve the best performance at many sites. Real-time data replication is possible, and has minimal impact on the server.

Master-Server 중 한 대는 Primary Server로서 기능을 하다가 Fail시 Standby Server가 임무를 수행. 데이터 입력(Insert, Update, Delete)은 모두 마스터 서버에서 이루어지고, 데이터 불러오기(Select)는 슬레이브 서버들이 담당
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