mysqlcluster官⽅⽂档
17.1. MySQL Cluster Overview
[]
MySQL Cluster is a technology that enables clustering of in-memory databases in a shared-nothing system. The shared-nothing architecture enables the system to work with very inexpensive hardware, and with a minimum of specific requirements for hardware or software.
MySQL Cluster is designed not to have any single point of failure. In a shared-nothing system, each component is expected to have its own memory and disk, and the use of shared storage mechanisms such as network shares, network file systems, and SANs is not recommended or supported.
MySQL Cluster integrates the standard MySQL server with an in-memory clustered storage engine called (which stands
for “N etwork D ata B ase”). In our documentation, the term  refers to the part of the setup that is specific to the storage engine,
whereas “MySQL Cluster” refers to the combination of one or more MySQL servers with the  storage engine.
A MySQL Cluster consists of a set of computers, known as hosts, each running one or more processes. These processes, known as nodes, may include MySQL servers (for access to ND
B data), data nodes (for storage of the data), one or more management servers, and possibly other specialized data access programs. The relationship of these components in a MySQL Cluster is shown here:
MySQL Cluster Components
All these programs work together to form a MySQL Cluster (see . When data is stored by the  storage engine, the tables (and table data) are stored in the data nodes. Such tables are directly accessible from all other MySQL servers (SQL nodes) in the cluster. Thus, in a payroll application storing data in a cluster, if one application updates the salary of an employee, all other MySQL servers that query this data can see this change immediately.
Although a MySQL Cluster SQL node uses the  server daemon, it differs in a number of critical respe
cts from the  binary supplied with the MySQL 5.6 distributions, and the two versions of  are not interchangeable.
In addition, a MySQL server that is not connected to a MySQL Cluster cannot use the  storage engine and cannot access any MySQL Cluster data.
The data stored in the data nodes for MySQL Cluster can be mirrored; the cluster can handle failures of individual data nodes with no other impact than that a small number of transactions are aborted due to losing the transaction state. Because transactional applications are expected to handle transaction failure, this should not be a source of problems.
mysql帮助文档
Individual nodes can be stopped and restarted, and can then rejoin the system (cluster). Rolling restarts (in which all nodes are restarted in turn) are used in making configuration changes and software upgrades (see). Rolling restarts are also used as part of the process of adding new data nodes online (see ). For more information about data nodes, how they are organized in a MySQL Cluster, and how they handle and store MySQL Cluster data, see .
Backing up and restoring MySQL Cluster databases can be done using the NDB-native functionality found in the MySQL Cluster management client and the  program included in the MySQL Cluster dist
ribution. For more information, see , and . You can also use the standard MySQL functionality provided for this purpose in  and the MySQL server. See , for more information.
MySQL Cluster nodes can use a number of different transport mechanisms for inter-node communications, including TCP/IP using standard 100 Mbps or faster Ethernet hardware. It is also possible to use the high-speed Scalable Coherent Interface (SCI) protocol with MySQL Cluster, although this is not required to use MySQL Cluster. SCI requires special hardware and software; see , for more about SCI and using it with MySQL Cluster.

版权声明：本站内容均来自互联网，仅供演示用，请勿用于商业和其他非法用途。如果侵犯了您的权益请与我们联系QQ:729038198，我们将在24小时内删除。