Computer-level examination system to use the cluster, the goal is to set up the cluster, to ensure that a library dang, will not affect the operation of the program. So under the leadership of Menghai brother Siang began my first build MySQL cluster, first read some information about the cluster, and then according to step by step of the whole, encountered some problems, here I encountered problems and solutions to share.
"What is it?"
Cluster (cluster) technology is a relatively new technology, through clustering technology, can be paid at a lower cost in the performance, reliability, flexibility of relatively high returns, and its task scheduling is the core technology in the cluster system.
MySQL Cluster technology provides redundancy for MySQL data in distributed system, and enhances security, so that single MySQL server failure does not have a huge negative effect on the system, and the stability of the system is guaranteed.
A MySQL cluster consists of three nodes: the management node, the data node, and the SQL node. The boot order is: Management node, data node, SQL node. The management node can only be one, and the data nodes and SQL nodes may be set as many as needed.
Management node: (also known as the Management Server) is primarily responsible for managing data nodes and SQL nodes, as well as cluster configuration files and cluster log files. It monitors the working state of other nodes and is capable of starting, shutting down, or restarting a node. The other nodes retrieve the configuration data from the management node and send the event information to the management node and write to the cluster log when the data node has a new event.
Data node: Responsible for storing data
SQL node: Use it for SQL operations.
"Why"
Why to use the cluster also through its advantages, the cluster with a lower cost, in terms of performance, flexible availability of a great improvement
"Advantages"
High scalability: Server clusters are highly scalable. As demand and load grow, more servers can be added to the cluster system. In such a configuration, multiple servers can perform the same application and database operations.
High availability: The ability to prevent system failures or to recover automatically from failures without the need for operator intervention. By moving applications on a failed server to a backup server, the cluster system can increase uptime to more than 99.9%, significantly reducing server and application downtime.
High manageability: System administrators can remotely manage one or even a group of clusters as if they were in a standalone system.
"Disadvantage"
We know that the application in the cluster runs on only one server, and if the application fails, one of the other servers restarts the application, taking over the data area on the shared enclosure, and then re-functioning the application. We know that the entire application process takes three steps in general: Detect and confirm the failure, the backup server restarts the app, takes over the shared data area. Therefore, in the process of switching to spend a certain amount of time, in principle, depending on the size of the application to switch the time will be different, the larger the application of the longer the switch time.
"Summary"
This is the first blog of MySQL cluster, mainly introduces the basic knowledge of the cluster, the origin of the cluster, why use, as well as the advantages and disadvantages of the cluster, the next blog on the MySQL cluster in the Windows environment of the building process and in the construction process encountered problems and solutions.
MySQL Cluster Setup Tutorial-Basic article